Mark Jit
Mark Jit
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Chair and Professor of the Department of Global and Environmental Health
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Professional overview
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Mark Jit is the inaugural chair and a professor in the Department of Global and Environmental Health. He was formerly head of the Department of Infectious Disease Epidemiology & Dynamics and co-director of the Global Health Economics Centre (GHECO) at the London School of Hygiene & Tropical Medicine (LSHTM). He holds honorary appointments at LSHTM as well as the University of Hong Kong (HKU) and the National University of Singapore (NUS).
Dr. Jit’s research focuses on epidemiological and economic modeling of vaccines to support evidence-based public health decision making. He has published papers covering a range of vaccine-preventable or potentially vaccine-preventable diseases including COVID-19, measles, HPV, pneumococcus, rotavirus, influenza, Group B Streptococcus, dengue, EV71 and RSV as well as methodological papers advancing the ways vaccines are evaluated. This work has influenced many of the major changes to immunization policy in countries around the world. Dr. Jit has served on a number of expert advisory committees in the UK as well as for international organizations such as the World Health Organization. He also organises or contributes to academic and professional courses on vaccine modeling, economics and decision science around the world.
Dr. Jit received his BSc and PhD in Mathematics from University College London, specializing in mathematical biology, and a Master of Public Health degree from King’s College London.
Visit Dr. Jit's Google Scholar's page to learn more about his research portfolio.
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Education
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BSc, Mathematics, University College LondonPhD, Mathematics, University College LondonMPH, Public Health, King's College London
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Honors and awards
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Clarivate Highly Cited Researcher (20222023)Fellow of the Academy of Medical Sciences (2023)Training Fund Award, Health Protection Agency (2007)Andrew Rosen Prize, University College London (1999)Institute of Mathematics and its Applications Award (1998)Departmental Research Studentship, University College London (1998)Student Union Commendation, University College London (1997)Fillon Prize, University College London (1996)Pathfinder Award, University College London (1995)
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Publications
Publications
Implications of the school-household network structure on SARS-CoV-2 transmission under school reopening strategies in England
AbstractCMMID COVID-19 Working Group, A., Munday, J. D., Sherratt, K., Meakin, S., Endo, A., Pearson, C. A., Hellewell, J., Abbott, S., Bosse, N. I., Eggo, R. M., Simons, D., O’Reilly, K., Russell, T. W., Lowe, R., Leclerc, Q. J., Emery, J. C., Klepac, P., Nightingale, E. S., Quaife, M., … Funk, S. (n.d.).Publication year
2021Journal title
Nature communicationsVolume
12Issue
1AbstractIn early 2020 many countries closed schools to mitigate the spread of SARS-CoV-2. Since then, governments have sought to relax the closures, engendering a need to understand associated risks. Using address records, we construct a network of schools in England connected through pupils who share households. We evaluate the risk of transmission between schools under different reopening scenarios. We show that whilst reopening select year-groups causes low risk of large-scale transmission, reopening secondary schools could result in outbreaks affecting up to 2.5 million households if unmitigated, highlighting the importance of careful monitoring and within-school infection control to avoid further school closures or other restrictions.Importance of patient bed pathways and length of stay differences in predicting COVID-19 hospital bed occupancy in England
AbstractISARIC4C investigators, A., CMMID COVID-19 Working Group, A., Leclerc, Q. J., Fuller, N. M., Keogh, R. H., Diaz-Ordaz, K., Sekula, R., Semple, M. G., Baillie, J. K., Openshaw, P. J., Carson, G., Alex, B., Bach, B., Barclay, W. S., Bogaert, D., Chand, M., Cooke, G. S., Docherty, A. B., Dunning, J., … Jit, M. (n.d.).Publication year
2021Journal title
BMC health services researchVolume
21Issue
1AbstractBackground: Predicting bed occupancy for hospitalised patients with COVID-19 requires understanding of length of stay (LoS) in particular bed types. LoS can vary depending on the patient’s “bed pathway” - the sequence of transfers of individual patients between bed types during a hospital stay. In this study, we characterise these pathways, and their impact on predicted hospital bed occupancy. Methods: We obtained data from University College Hospital (UCH) and the ISARIC4C COVID-19 Clinical Information Network (CO-CIN) on hospitalised patients with COVID-19 who required care in general ward or critical care (CC) beds to determine possible bed pathways and LoS. We developed a discrete-time model to examine the implications of using either bed pathways or only average LoS by bed type to forecast bed occupancy. We compared model-predicted bed occupancy to publicly available bed occupancy data on COVID-19 in England between March and August 2020. Results: In both the UCH and CO-CIN datasets, 82% of hospitalised patients with COVID-19 only received care in general ward beds. We identified four other bed pathways, present in both datasets: “Ward, CC, Ward”, “Ward, CC”, “CC” and “CC, Ward”. Mean LoS varied by bed type, pathway, and dataset, between 1.78 and 13.53 days. For UCH, we found that using bed pathways improved the accuracy of bed occupancy predictions, while only using an average LoS for each bed type underestimated true bed occupancy. However, using the CO-CIN LoS dataset we were not able to replicate past data on bed occupancy in England, suggesting regional LoS heterogeneities. Conclusions: We identified five bed pathways, with substantial variation in LoS by bed type, pathway, and geography. This might be caused by local differences in patient characteristics, clinical care strategies, or resource availability, and suggests that national LoS averages may not be appropriate for local forecasts of bed occupancy for COVID-19. Trial registration: The ISARIC WHO CCP-UK study ISRCTN66726260 was retrospectively registered on 21/04/2020 and designated an Urgent Public Health Research Study by NIHR.Incidence and disease burden of herpes zoster in the population aged ≥50 years in China : Data from an integrated health care network
AbstractSun, X., Wei, Z., Lin, H., Jit, M., Li, Z., & Fu, C. (n.d.).Publication year
2021Journal title
Journal of InfectionVolume
82Issue
2Page(s)
253-260AbstractBackground: Herpes zoster (HZ) mainly affects elderly and immunocompromised individuals and is characterized by a painful vesicular rash. Data on the epidemiology of HZ, particularly in unvaccinated individuals aged ≥50 years, are still limited in China. Thus, this study aimed to evaluate the epidemiological features, disease burden, and associated risk factors of HZ in the population aged ≥50 years in China. Methods: We evaluated HZ patients who were aged ≥50 years between January 1, 2015 and December 31, 2017 in the electronic health record database of Yinzhou district. HZ and its complications were identified using ICD-10 codes. In addition, post-herpetic neuralgia (PHN) as a complication of HZ was defined as pain occurring or persisting 90 days after rash onset. The disease burden was estimated according to the duration of hospitalization, frequency of visits, pharmacological treatment cost, and examination cost. Cox proportional hazards regression was used to investigate the associated risk factors for HZ. Results: The overall incidence of HZ was 6.64 per 1000 person-years. Of the 4,313 initial episodes from 2015 to 2017, there were 99 recurrent cases. In total, 7.26% and 3.94% of the HZ patients had PHN and other complications, respectively. The average frequency of outpatient visits was significantly lower in patients with initial disease than that in patients with recurrence (3.6 vs. 6.7 per patient). The mean duration of hospital stay was longer in the recurrent episode than that in the initial episode (24.0 vs. 21.6 days). The inpatient and outpatient cost per new-onset HZ was approximately ¥8116.9 and ¥560.2 per patient, respectively. Age; female sex; suburban residency; and presence of immunocompromised disease, hypertension, or diabetes were significantly associated with the development of HZ. Conclusion: The incidence and recurrence rates of HZ showed different trends with increasing age. The presence of HZ-related complications increased the direct medical costs. Our findings help provide a basis for developing appropriate strategies for HZ prevention and control.Increased mortality in community-tested cases of SARS-CoV-2 lineage B.1.1.7
AbstractCMMID COVID-19 Working Group, A., Davies, N. G., Jarvis, C. I., van Zandvoort, K., Clifford, S., Sun, F. Y., Funk, S., Medley, G., Jafari, Y., Meakin, S. R., Lowe, R., Quaife, M., Waterlow, N. R., Eggo, R. M., Lei, J., Koltai, M., Krauer, F., Tully, D. C., Munday, J. D., … Brady, O. (n.d.).Publication year
2021Journal title
NatureVolume
593Issue
7858Page(s)
270-274AbstractSARS-CoV-2 lineage B.1.1.7, a variant that was first detected in the UK in September 20201, has spread to multiple countries worldwide. Several studies have established that B.1.1.7 is more transmissible than pre-existing variants, but have not identified whether it leads to any change in disease severity2. Here we analyse a dataset that links 2,245,263 positive SARS-CoV-2 community tests and 17,452 deaths associated with COVID-19 in England from 1 November 2020 to 14 February 2021. For 1,146,534 (51%) of these tests, the presence or absence of B.1.1.7 can be identified because mutations in this lineage prevent PCR amplification of the spike (S) gene target (known as S gene target failure (SGTF)1). On the basis of 4,945 deaths with known SGTF status, we estimate that the hazard of death associated with SGTF is 55% (95% confidence interval, 39–72%) higher than in cases without SGTF after adjustment for age, sex, ethnicity, deprivation, residence in a care home, the local authority of residence and test date. This corresponds to the absolute risk of death for a 55–69-year-old man increasing from 0.6% to 0.9% (95% confidence interval, 0.8–1.0%) within 28 days of a positive test in the community. Correcting for misclassification of SGTF and missingness in SGTF status, we estimate that the hazard of death associated with B.1.1.7 is 61% (42–82%) higher than with pre-existing variants. Our analysis suggests that B.1.1.7 is not only more transmissible than pre-existing SARS-CoV-2 variants, but may also cause more severe illness.Informing Global Cost-Effectiveness Thresholds Using Country Investment Decisions : Human Papillomavirus Vaccine Introductions in 2006-2018
AbstractJit, M. (n.d.).Publication year
2021Journal title
Value in HealthVolume
24Issue
1Page(s)
61-66AbstractObjectives: Cost-effectiveness analysis can guide decision making about health interventions, but the appropriate cost-effectiveness threshold to use is unclear in most countries. The World Health Organization (WHO) recommends vaccinating girls 9 to 14 years against human papillomavirus (HPV), but over half the world's countries have not introduced it. This study aimed to investigate whether country-level decisions about HPV vaccine introduction are consistent with a particular cost-effectiveness threshold, and to estimate what that threshold may be. Methods: The cost-effectiveness of vaccinating 12-year-old girls was estimated in 179 countries using the Papillomavirus Rapid Interface for Modelling and Economics (PRIME) model, together with vaccine price data from World Health Organization's Market Information for Access to Vaccines database. In each year from 2006 to 2018, countries were categorized based on (1) whether they had introduced HPV vaccination, and (2) whether the incremental cost-effectiveness ratio for HPV vaccine introduction fell below a certain cost-effectiveness threshold. Results: A cost-effectiveness threshold of 60% to 65% of GDP per capita has the best ability to discriminate countries that introduced vaccination, with a diagnostic odds ratio of about 7. For low-income countries the optimal threshold was lower, at 30% to 40% of GDP per capita. Conclusions: A cost-effectiveness threshold has some ability to discriminate between HPV vaccine introducer and non-introducer countries, although the average threshold is below the widely used threshold of 1 GDP per capita. These results help explain the current pattern of HPV vaccine use globally. They also inform the extent to which cost-effectiveness thresholds proposed in the literature reflect countries’ actual investment decisions.Lives saved with vaccination for 10 pathogens across 112 countries in a pre-covid-19 world
AbstractToor, J., Echeverria-Londono, S., Li, X., Abbas, K., Carter, E. D., Clapham, H. E., Clark, A., de Villiers, M. J., Eilertson, K., Ferrari, M., Gamkrelidze, I., Hallett, T. B., Hinsley, W. R., Hogan, D., Huber, J. H., Jackson, M. L., Jean, K., Jit, M., Karachaliou, A., … Gaythorpe, K. A. (n.d.).Publication year
2021Journal title
eLifeVolume
10AbstractBackground: Vaccination is one of the most effective public health interventions. We investigate the impact of vaccination activities for Haemophilus influenzae type b, hepatitis B, human papillomavirus, Japanese encephalitis, measles, Neisseria meningitidis serogroup A, rotavirus, rubella, Streptococcus pneumoniae, and yellow fever over the years 2000–2030 across 112 countries. Methods: Twenty-one mathematical models estimated disease burden using standardised demographic and immunisation data. Impact was attributed to the year of vaccination through vaccine-activity-stratified impact ratios. Results: We estimate 97 (95%CrI[80, 120]) million deaths would be averted due to vaccination activities over 2000–2030, with 50 (95%CrI[41, 62]) million deaths averted by activities between 2000 and 2019. For children under-5 born between 2000 and 2030, we estimate 52 (95%CrI[41, 69]) million more deaths would occur over their lifetimes without vaccination against these diseases. Conclusions: This study represents the largest assessment of vaccine impact before COVID-19-related disruptions and provides motivation for sustaining and improving global vaccination coverage in the future.Modeling the effect of vaccination on selection for antibiotic resistance in Streptococcus pneumoniae
AbstractDavies, N. G., Flasche, S., Jit, M., & Atkins, K. E. (n.d.).Publication year
2021Journal title
Science Translational MedicineVolume
13Issue
606AbstractVaccines against bacterial pathogens can protect recipients from becoming infected with potentially antibiotic-resistant pathogens. However, by altering the selective balance between antibiotic-sensitive and antibiotic-resistant bacterial strains, vaccines may also suppress-or spread-antibiotic resistance among unvaccinated individuals. Predicting the outcome of vaccination requires knowing what drives selection for drug-resistant bacterial pathogens and what maintains the circulation of both antibiotic-sensitive and antibiotic-resistant strains of bacteria. To address this question, we used mathematical modeling and data from 2007 on penicillin consumption and penicillin nonsusceptibility in Streptococcus pneumoniae (pneumococcus) invasive isolates from 27 European countries. We show that the frequency of penicillin resistance in S. pneumoniae can be explained by between-host diversity in antibiotic use, heritable diversity in pneumococcal carriage duration, or frequency-dependent selection brought about by within-host competition between antibiotic-resistant and antibiotic-sensitive S. pneumoniae strains. We used our calibrated models to predict the impact of non-serotype-specific pneumococcal vaccination upon the prevalence of S. pneumoniae carriage, incidence of disease, and frequency of S. pneumoniae antibiotic resistance. We found that the relative strength and directionality of competition between drug-resistant and drug-sensitive pneumococcal strains was the most important determinant of whether vaccination would promote, inhibit, or have little effect upon the evolution of antibiotic resistance. Last, we show that country-specific differences in pathogen transmission substantially altered the predicted impact of vaccination, highlighting that policies for managing antibiotic resistance with vaccines must be tailored to a specific pathogen and setting.Models of COVID-19 vaccine prioritisation : a systematic literature search and narrative review
AbstractSaadi, N., Chi, Y. L., Ghosh, S., Eggo, R. M., McCarthy, C. V., Quaife, M., Dawa, J., Jit, M., & Vassall, A. (n.d.).Publication year
2021Journal title
BMC MedicineVolume
19Issue
1AbstractBackground: How best to prioritise COVID-19 vaccination within and between countries has been a public health and an ethical challenge for decision-makers globally. We reviewed epidemiological and economic modelling evidence on population priority groups to minimise COVID-19 mortality, transmission, and morbidity outcomes. Methods: We searched the National Institute of Health iSearch COVID-19 Portfolio (a database of peer-reviewed and pre-print articles), Econlit, the Centre for Economic Policy Research, and the National Bureau of Economic Research for mathematical modelling studies evaluating the impact of prioritising COVID-19 vaccination to population target groups. The first search was conducted on March 3, 2021, and an updated search on the LMIC literature was conducted from March 3, 2021, to September 24, 2021. We narratively synthesised the main study conclusions on prioritisation and the conditions under which the conclusions changed. Results: The initial search identified 1820 studies and 36 studies met the inclusion criteria. The updated search on LMIC literature identified 7 more studies. 43 studies in total were narratively synthesised. 74% of studies described outcomes in high-income countries (single and multi-country). We found that for countries seeking to minimise deaths, prioritising vaccination of senior adults was the optimal strategy and for countries seeking to minimise cases the young were prioritised. There were several exceptions to the main conclusion, notably that reductions in deaths could be increased if groups at high risk of both transmission and death could be further identified. Findings were also sensitive to the level of vaccine coverage. Conclusion: The evidence supports WHO SAGE recommendations on COVID-19 vaccine prioritisation. There is, however, an evidence gap on optimal prioritisation for low- and middle-income countries, studies that included an economic evaluation, and studies that explore prioritisation strategies if the aim is to reduce overall health burden including morbidity.Mortality, neurodevelopmental impairments, and economic outcomes after invasive group B streptococcal disease in early infancy in Denmark and the Netherlands : a national matched cohort study
AbstractHorváth-Puhó, E., van Kassel, M. N., Gonçalves, B. P., de Gier, B., Procter, S. R., Paul, P., van der Ende, A., Søgaard, K. K., Hahné, S. J., Chandna, J., Schrag, S. J., van de Beek, D., Jit, M., Sørensen, H. T., Bijlsma, M. W., & Lawn, J. E. (n.d.).Publication year
2021Journal title
The Lancet Child and Adolescent HealthVolume
5Issue
6Page(s)
398-407AbstractBackground: Group B Streptococcus (GBS) disease is a leading cause of neonatal death, but its long-term effects have not been studied after early childhood. The aim of this study was to assess long-term mortality, neurodevelopmental impairments (NDIs), and economic outcomes after infant invasive GBS (iGBS) disease up to adolescence in Denmark and the Netherlands. Methods: For this cohort study, children with iGBS disease were identified in Denmark and the Netherlands using national medical and administrative databases and culture results that confirmed their diagnoses. Exposed children were defined as having a history of iGBS disease (sepsis, meningitis, or pneumonia) by the age of 89 days. For each exposed child, ten unexposed children were randomly selected and matched by sex, year and month of birth, and gestational age. Mortality data were analysed with the use of Cox proportional hazards models. NDI data up to adolescence were captured from discharge diagnoses in the National Patient Registry (Denmark) and special educational support records (the Netherlands). Health care use and household income were also compared between the exposed and unexposed cohorts. Findings: 2258 children—1561 in Denmark (born from Jan 1, 1997 to Dec 31, 2017) and 697 in the Netherlands (born from Jan 1, 2000 to Dec 31, 2017)—were identified to have iGBS disease and followed up for a median of 14 years (IQR 7–18) in Denmark and 9 years (6–11) in the Netherlands. 366 children had meningitis, 1763 had sepsis, and 129 had pneumonia (in Denmark only). These children were matched with 22 462 children with no history of iGBS disease. iGBS meningitis was associated with an increased mortality at age 5 years (adjusted hazard ratio 4·08 [95% CI 1·78–9·35] for Denmark and 6·73 [3·76–12·06] for the Netherlands). Any iGBS disease was associated with an increased risk of NDI at 10 years of age, both in Denmark (risk ratio 1·77 [95% CI 1·44–2·18]) and the Netherlands (2·28 [1·64–3·17]). A history of iGBS disease was associated with more frequent outpatient clinic visits (incidence rate ratio 1·93 [95% CI 1·79–2·09], pMulti-country collaboration in responding to global infectious disease threats : lessons for Europe from the COVID-19 pandemic
AbstractJit, M., Ananthakrishnan, A., McKee, M., Wouters, O. J., Beutels, P., & Teerawattananon, Y. (n.d.).Publication year
2021Journal title
The Lancet Regional Health - EuropeVolume
9AbstractSince 2005, the world has faced several public health emergencies of international concern arising from infectious disease outbreaks. Of these, the COVID-19 pandemic has had by far the greatest health and economic consequences. During these emergencies, responses taken by one country often have an impact on other countries. The implication is that coordination between countries is likely to achieve better outcomes, individually and collectively, than each country independently pursuing its own self-interest. During the COVID-19 pandemic, gaps in multilateral cooperation on research and information sharing, vaccine development and deployment, and travel policies have hampered the speed and equity of global recovery. In this Health Policy article, we explore how multilateral collaboration between countries is crucial to successful responses to public health emergencies linked to infectious disease outbreaks. Responding to future global infectious disease threats and other health emergencies will require the creation of stronger mechanisms for multilateral collaboration before they arise. A change to the governance of multilateral institutions is a logical next step, with a focus on providing equal ownership and leadership opportunities to all member countries. Europe can be an example and advocate for stronger and better governed multilateral institutions.Optimal human papillomavirus vaccination strategies to prevent cervical cancer in low-income and middle-income countries in the context of limited resources : a mathematical modelling analysis
AbstractDrolet, M., Laprise, J. F., Martin, D., Jit, M., Bénard, É., Gingras, G., Boily, M. C., Alary, M., Baussano, I., Hutubessy, R., & Brisson, M. (n.d.).Publication year
2021Journal title
The Lancet Infectious DiseasesVolume
21Issue
11Page(s)
1598-1610AbstractBackground: Introduction of human papillomavirus (HPV) vaccination has been slow in low-income and middle-income countries (LMICs) because of resource constraints and worldwide shortage of vaccine supplies. To help inform WHO recommendations, we modelled various HPV vaccination strategies to examine the optimal use of limited vaccine supplies and best allocation of scarce resources in LMICs in the context of the WHO global call to eliminate cervical cancer as a public health problem. Methods: In this mathematical modelling analysis, we developed HPV-ADVISE LMIC, a transmission-dynamic model of HPV infection and diseases calibrated to four LMICs: India, Vietnam, Uganda, and Nigeria. For different vaccination strategies that encompassed use of a nine-valent vaccine (or a two-valent or four-valent vaccine assuming high cross-protection), we estimated three outcomes: reduction in the age-standardised rate of cervical cancer, number of doses needed to prevent one case of cervical cancer (NNV; as a measure of efficiency), and the incremental cost-effectiveness ratio (ICER; in 2017 international $ per disability-adjusted life-year [DALY] averted). We examined different vaccination strategies by varying the ages of routine HPV vaccination and number of age cohorts vaccinated, the population targeted, and the number of doses used. In our base case, we assumed 100% lifetime protection against HPV-16, HPV-18, HPV-31, HPV-33, HPV-45, HPV-52, and HPV-58; vaccination coverage of 80%; and a time horizon of 100 years. For the cost-effectiveness analysis, we used a 3% discount rate. Elimination of cervical cancer was defined as an age-standardised incidence of less than four cases per 100 000 woman-years. Findings: We predicted that HPV vaccination could lead to cervical cancer elimination in Vietnam, India, and Nigeria, but not in Uganda. Compared with no vaccination, strategies that involved vaccinating girls aged 9–14 years with two doses were predicted to be the most efficient and cost-effective in all four LMICs. NNV ranged from 78 to 381 and ICER ranged from $28 per DALY averted to $1406 per DALY averted depending on the country. The most efficient and cost-effective strategies were routine vaccination of girls aged 14 years, with or without a later switch to routine vaccination of girls aged 9 years, and routine vaccination of girls aged 9 years with a 5-year extended interval between doses and a catch-up programme at age 14 years. Vaccinating boys (aged 9–14 years) or women aged 18 years or older resulted in substantially higher NNVs and ICERs. Interpretation: We identified two strategies that could maximise efforts to prevent cervical cancer in LMICs given constraints on vaccine supplies and costs and that would allow a maximum of LMICs to introduce HPV vaccination. Funding: World Health Organization, Canadian Institute of Health Research, Fonds de recherche du Québec–Santé, Compute Canada, PATH, and The Bill & Melinda Gates Foundation. Translations: For the French and Spanish translations of the abstract see Supplementary Materials section.Projecting contact matrices in 177 geographical regions : An update and comparison with empirical data for the COVID-19 era
AbstractPrem, K., van Zandvoort, K., Klepac, P., Eggo, R. M., Davies, N. G., Cook, A. R., & Jit, M. (n.d.).Publication year
2021Journal title
PLoS computational biologyVolume
17Issue
7Page(s)
1DUMMUYAbstractMathematical models have played a key role in understanding the spread of directly-transmissible infectious diseases such as Coronavirus Disease 2019 (COVID-19), as well as the effectiveness of public health responses. As the risk of contracting directly-transmitted infections depends on who interacts with whom, mathematical models often use contact matrices to characterise the spread of infectious pathogens. These contact matrices are usually generated from diary-based contact surveys. However, the majority of places in the world do not have representative empirical contact studies, so synthetic contact matrices have been constructed using more widely available setting-specific survey data on household, school, classroom, and workplace composition combined with empirical data on contact patterns in Europe. In 2017, the largest set of synthetic contact matrices to date were published for 152 geographical locations. In this study, we update these matrices with the most recent data and extend our analysis to 177 geographical locations. Due to the observed geographic differences within countries, we also quantify contact patterns in rural and urban settings where data is available. Further, we compare both the 2017 and 2020 synthetic matrices to out-of-sample empirically-constructed contact matrices, and explore the effects of using both the empirical and synthetic contact matrices when modelling physical distancing interventions for the COVID-19 pandemic. We found that the synthetic contact matrices show qualitative similarities to the contact patterns in the empirically-constructed contact matrices. Models parameterised with the empirical and synthetic matrices generated similar findings with few differences observed in age groups where the empirical matrices have missing or aggregated age groups. This finding means that synthetic contact matrices may be used in modelling outbreaks in settings for which empirical studies have yet to be conducted.Projections of human papillomavirus (HPV) vaccination impact in Ethiopia, India, Nigeria and Pakistan : A comparative modelling study
AbstractPortnoy, A., Abbas, K., Sweet, S., Kim, J. J., & Jit, M. (n.d.).Publication year
2021Journal title
BMJ Global HealthVolume
6Issue
11AbstractIntroduction Cervical cancer is the second most common cancer among women in Ethiopia, India, Nigeria and Pakistan. Our study objective was to assess similarities and differences in vaccine-impact projections through comparative modelling analysis by independently estimating the potential health impact of human papillomavirus (HPV) vaccination. Methods Using two widely published models (Harvard and Papillomavirus Rapid Interface for Modelling and Economics (PRIME)) to estimate HPV vaccination impact, we simulated a vaccination scenario of 90% annual coverage among 10 cohorts of 9-year-old girls from 2021 to 2030 in Ethiopia, India, Nigeria and Pakistan. We estimated potential health impact in terms of cervical cancer cases, deaths and disability-adjusted life years averted among vaccinated cohorts from the time of vaccination until 2100. We harmonised the two models by standardising input data to comparatively estimate HPV vaccination impact. Results Prior to harmonising model assumptions, the range between PRIME and Harvard models for number of cervical cancer cases averted by HPV vaccination was: 262 000 to 2 70 000 in Ethiopia; 1 640 000 to 1 970 000 in India; 330 000 to 3 36 000 in Nigeria and 111 000 to 1 33 000 in Pakistan. When harmonising model assumptions, alignment on HPV type distribution significantly narrowed differences in vaccine-impact estimates. Conclusion Despite model differences, the Harvard and PRIME models yielded similar vaccine-impact estimates. The main differences in estimates are due to variation in interpretation around data on cervical cancer attribution to HPV-16/18. As countries make progress towards WHO targets for cervical cancer elimination, continued explorations of underlying differences in model inputs, assumptions and results when examining cervical cancer prevention policy will be critical.Quantifying long-term health and economic outcomes for survivors of group B Streptococcus invasive disease in infancy : Protocol of a multi-country study in Argentina, India, Kenya, Mozambique and South Africa
AbstractProcter, S. R., Paul, P., Dangor, Z., Bassat, Q., Abubakar, A., Santhanam, S., Libster, R., Gonçalves, B. P., Madhi, S. A., Bardají, A., Mwangome, E., Mabrouk, A., John, H. B., Sánchez Yanotti, C., Chandna, J., Sithole, P., Mucasse, H., Katana, P. V., Koukounari, A., … Lawn, J. E. (n.d.).Publication year
2021Journal title
Gates Open ResearchVolume
4AbstractSepsis and meningitis due to invasive group B Streptococcus (iGBS) disease during early infancy is a leading cause of child mortality. Recent systematic estimates of the worldwide burden of GBS suggested that there are 319,000 cases of infant iGBS disease each year, and an estimated 147,000 stillbirths and young-infant deaths, with the highest burden occurring in Sub-Saharan Africa. The following priority data gaps were highlighted: (1) long-term outcome data after infant iGBS, including mild disability, to calculate quality-adjusted life years (QALYs) or disability-adjusted life years (DALYs) and (2) economic burden for iGBS survivors and their families. Geographic data gaps were also noted with few studies from low- and middle- income countries (LMIC), where the GBS burden is estimated to be the highest. In this paper we present the protocol for a multi-country matched cohort study designed to estimate the risk of long-term neurodevelopmental impairment (NDI), socioemotional behaviors, and economic outcomes for children who survive invasive GBS disease in Argentina, India, Kenya, Mozambique, and South Africa. Children will be identified from health demographic surveillance systems, hospital records, and among participants of previous epidemiological studies. The children will be aged between 18 months to 17 years. A tablet-based custom-designed application will be used to capture data from direct assessment of the child and interviews with the main caregiver. In addition, a parallel sub-study will prospectively measure the acute costs of hospitalization due to neonatal sepsis or meningitis, irrespective of underlying etiology. In summary, these data are necessary to characterize the consequences of iGBS disease and enable the advancement of effective strategies for survivors to reach their developmental and economic potential. In particular, our study will inform the development of a full public health value proposition on maternal GBS immunization that is being coordinated by the World Health Organization.Quarantine and testing strategies in contact tracing for SARS-CoV-2 : a modelling study
AbstractCentre for the Mathematical Modelling of Infectious Diseases COVID-19 working group, A., Quilty, B. J., Clifford, S., Hellewell, J., Russell, T. W., Kucharski, A. J., Flasche, S., Edmunds, W. J., Atkins, K. E., Foss, A. M., Waterlow, N. R., Abbas, K., Lowe, R., Pearson, C. A., Funk, S., Rosello, A., Knight, G. M., Bosse, N. I., Procter, S. R., … Davies, N. G. (n.d.).Publication year
2021Journal title
The Lancet Public HealthVolume
6Issue
3Page(s)
e175-e183AbstractBackground: In most countries, contacts of confirmed COVID-19 cases are asked to quarantine for 14 days after exposure to limit asymptomatic onward transmission. While theoretically effective, this policy places a substantial social and economic burden on both the individual and wider society, which might result in low adherence and reduced policy effectiveness. We aimed to assess the merit of testing contacts to avert onward transmission and to replace or reduce the length of quarantine for uninfected contacts. Methods: We used an agent-based model to simulate the viral load dynamics of exposed contacts, and their potential for onward transmission in different quarantine and testing strategies. We compared the performance of quarantines of differing durations, testing with either PCR or lateral flow antigen (LFA) tests at the end of quarantine, and daily LFA testing without quarantine, against the current 14-day quarantine strategy. We also investigated the effect of contact tracing delays and adherence to both quarantine and self-isolation on the effectiveness of each strategy. Findings: Assuming moderate levels of adherence to quarantine and self-isolation, self-isolation on symptom onset alone can prevent 37% (95% uncertainty interval [UI] 12–56) of onward transmission potential from secondary cases. 14 days of post-exposure quarantine reduces transmission by 59% (95% UI 28–79). Quarantine with release after a negative PCR test 7 days after exposure might avert a similar proportion (54%, 95% UI 31–81; risk ratio [RR] 0·94, 95% UI 0·62–1·24) to that of the 14-day quarantine period, as would quarantine with a negative LFA test 7 days after exposure (50%, 95% UI 28–77; RR 0·88, 0·66–1·11) or daily testing without quarantine for 5 days after tracing (50%, 95% UI 23–81; RR 0·88, 0·60–1·43) if all tests are returned negative. A stronger effect might be possible if individuals isolate more strictly after a positive test and if contacts can be notified faster. Interpretation: Testing might allow for a substantial reduction in the length of, or replacement of, quarantine with a small excess in transmission risk. Decreasing test and trace delays and increasing adherence will further increase the effectiveness of these strategies. Further research is required to empirically evaluate the potential costs (increased transmission risk, false reassurance) and benefits (reduction in the burden of quarantine, increased adherence) of such strategies before adoption as policy. Funding: National Institute for Health Research, UK Research and Innovation, Wellcome Trust, EU Horizon 2021, and the Bill & Melinda Gates Foundation.Real-time monitoring of COVID-19 dynamics using automated trend fitting and anomaly detection
AbstractJombart, T., Ghozzi, S., Schumacher, D., Taylor, T. J., Leclerc, Q. J., Jit, M., Flasche, S., Greaves, F., Ward, T., Eggo, R. M., Nightingale, E., Meakin, S., Brady, O. J., Medley, G. F., Höhle, M., & Edmunds, W. J. (n.d.).Publication year
2021Journal title
Philosophical Transactions of the Royal Society B: Biological SciencesVolume
376Issue
1829AbstractAs several countries gradually release social distancing measures, rapid detection of new localized COVID-19 hotspots and subsequent intervention will be key to avoiding large-scale resurgence of transmission. We introduce ASMODEE (automatic selection of models and outlier detection for epidemics), a new tool for detecting sudden changes in COVID-19 incidence. Our approach relies on automatically selecting the best (fitting or predicting) model from a range of user-defined time series models, excluding the most recent data points, to characterize the main trend in an incidence. We then derive prediction intervals and classify data points outside this interval as outliers, which provides an objective criterion for identifying departures from previous trends. We also provide a method for selecting the optimal breakpoints, used to define how many recent data points are to be excluded from the trend fitting procedure. The analysis of simulated COVID-19 outbreaks suggests ASMODEE compares favourably with a state-of-art outbreak-detection algorithm while being simpler and more flexible. As such, our method could be of wider use for infectious disease surveillance. We illustrate ASMODEE using publicly available data of National Health Service (NHS) Pathways reporting potential COVID-19 cases in England at a fine spatial scale, showing that the method would have enabled the early detection of the flare-ups in Leicester and Blackburn with Darwen, two to three weeks before their respective lockdown. ASMODEE is implemented in the free R package trendbreaker. This article is part of the theme issue 'Modelling that shaped the early COVID-19 pandemic response in the UK'.SARS-CoV-2 infection risk during delivery of childhood vaccination campaigns : a modelling study
AbstractCMMID COVID-19 Working Group, A., Procter, S. R., Abbas, K., Flasche, S., Griffiths, U., Hagedorn, B., O’Reilly, K. M., Waterlow, N. R., Villabona-Arenas, C. J., Munday, J. D., Medley, G. F., Lowe, R., Mee, P., Liu, Y., Gimma, A., van Zandvoort, K., Hellewell, J., Tully, D. C., Brady, O., … Jit, M. (n.d.).Publication year
2021Journal title
BMC MedicineVolume
19Issue
1AbstractBackground: The COVID-19 pandemic has disrupted the delivery of immunisation services globally. Many countries have postponed vaccination campaigns out of concern about infection risks to the staff delivering vaccination, the children being vaccinated, and their families. The World Health Organization recommends considering both the benefit of preventive campaigns and the risk of SARS-CoV-2 transmission when making decisions about campaigns during COVID-19 outbreaks, but there has been little quantification of the risks. Methods: We modelled excess SARS-CoV-2 infection risk to vaccinators, vaccinees, and their caregivers resulting from vaccination campaigns delivered during a COVID-19 epidemic. Our model used population age structure and contact patterns from three exemplar countries (Burkina Faso, Ethiopia, and Brazil). It combined an existing compartmental transmission model of an underlying COVID-19 epidemic with a Reed-Frost model of SARS-CoV-2 infection risk to vaccinators and vaccinees. We explored how excess risk depends on key parameters governing SARS-CoV-2 transmissibility, and aspects of campaign delivery such as campaign duration, number of vaccinations, and effectiveness of personal protective equipment (PPE) and symptomatic screening. Results: Infection risks differ considerably depending on the circumstances in which vaccination campaigns are conducted. A campaign conducted at the peak of a SARS-CoV-2 epidemic with high prevalence and without special infection mitigation measures could increase absolute infection risk by 32 to 45% for vaccinators and 0.3 to 0.5% for vaccinees and caregivers. However, these risks could be reduced to 3.6 to 5.3% and 0.1 to 0.2% respectively by use of PPE that reduces transmission by 90% (as might be achieved with N95 respirators or high-quality surgical masks) and symptomatic screening. Conclusions: SARS-CoV-2 infection risks to vaccinators, vaccinees, and caregivers during vaccination campaigns can be greatly reduced by adequate PPE, symptomatic screening, and appropriate campaign timing. Our results support the use of adequate risk mitigation measures for vaccination campaigns held during SARS-CoV-2 epidemics, rather than cancelling them entirely.Stark choices : Exploring health sector costs of policy responses to COVID-19 in low-income and middle-income countries
AbstractTorres-Rueda, S., Sweeney, S., Bozzani, F., Naylor, N. R., Baker, T., Pearson, C., Eggo, R., Procter, S. R., Davies, N., Quaife, M., Kitson, N., Keogh-Brown, M. R., Jensen, H. T., Saadi, N., Khan, M., Huda, M., Kairu, A., Zaidi, R., Barasa, E., … Vassall, A. (n.d.).Publication year
2021Journal title
BMJ Global HealthVolume
6Issue
12AbstractObjectives: COVID-19 has altered health sector capacity in low-income and middle-income countries (LMICs). Cost data to inform evidence-based priority setting are urgently needed. Consequently, in this paper, we calculate the full economic health sector costs of COVID-19 clinical management in 79 LMICs under different epidemiological scenarios. Methods: We used country-specific epidemiological projections from a dynamic transmission model to determine number of cases, hospitalisations and deaths over 1 year under four mitigation scenarios. We defined the health sector response for three base LMICs through guidelines and expert opinion. We calculated costs through local resource use and price data and extrapolated costs across 79 LMICs. Lastly, we compared cost estimates against gross domestic product (GDP) and total annual health expenditure in 76 LMICs. Results: COVID-19 clinical management costs vary greatly by country, ranging betweenStrategies to reduce the risk of SARS-CoV-2 importation from international travellers : Modelling estimations for the United Kingdom, July 2020
AbstractCMMID COVID-19 Working Group, A., Clifford, S., Quilty, B. J., Russell, T. W., Liu, Y., Chan, Y. W., Pearson, C. A., Eggo, R. M., Endo, A., Flasche, S., John Edmunds, W., Sherratt, K., Hué, S., Quaife, M., Bosse, N. I., Medley, G., Auzenbergs, M., Kucharski, A. J., Davies, N. G., … Abbas, K. (n.d.).Publication year
2021Journal title
EurosurveillanceVolume
26Issue
39AbstractBackground: To mitigate SARS-CoV-2 transmission risks from international air travellers, many countries implemented a combination of up to 14 days of self-quarantine upon arrival plus PCR testing in the early stages of the COVID-19 pandemic in 2020. Aim: To assess the effectiveness of quarantine and testing of international travellers to reduce risk of onward SARS-CoV-2 transmission into a destination country in the pre-COVID-19 vaccination era. Methods: We used a simulation model of air travellers arriving in the United Kingdom from the European Union or the United States, incorporating timing of infection stages while varying quarantine duration and timing and number of PCR tests. Results: Quarantine upon arrival with a PCR test on day 7 plus a 1-day delay for results can reduce the number of infectious arriving travellers released into the community by a median 94% (95% uncertainty interval (UI): 89–98) compared with a no quarantine/no test scenario. This reduction is similar to that achieved by a 14-day quarantine period (median>99%; 95% UI: 98–100). Even shorter quarantine periods can prevent a substantial amount of transmission; all strategies in which travellers spend at least 5 days (mean incubation period) in quarantine and have at least one negative test before release are highly effective (median reduction 89%; 95% UI: 83–95)). Conclusion: The effect of different screening strategies impacts asymptomatic and symptomatic individuals differently. The choice of an optimal quarantine and testing strategy for unvaccinated air travellers may vary based on the number of possible imported infections relative to domestic incidence.The CAPACITI Decision-Support Tool for National Immunization Programs
AbstractBotwright, S., Giersing, B. K., Meltzer, M. I., Kahn, A. L., Jit, M., Baltussen, R., El Omeiri, N., Biey, J. N., Moore, K. L., Thokala, P., Mwenda, J. M., Bertram, M., & Hutubessy, R. C. (n.d.).Publication year
2021Journal title
Value in HealthVolume
24Issue
8Page(s)
1150-1157AbstractObjectives: Immunization programs in low-income and middle-income countries (LMICs) are faced with an ever-growing number of vaccines of public health importance recommended by the World Health Organization, while also financing a greater proportion of the program through domestic resources. More than ever, national immunization programs must be equipped to contextualize global guidance and make choices that are best suited to their setting. The CAPACITI decision-support tool has been developed in collaboration with national immunization program decision makers in LMICs to structure and document an evidence-based, context-specific process for prioritizing or selecting among multiple vaccination products, services, or strategies. Methods: The CAPACITI decision-support tool is based on multi-criteria decision analysis, as a structured way to incorporate multiple sources of evidence and stakeholder perspectives. The tool has been developed iteratively in consultation with 12 countries across Africa, Asia, and the Americas. Results: The tool is flexible to existing country processes and can follow any type of multi-criteria decision analysis or a hybrid approach. It is structured into 5 sections: decision question, criteria for decision making, evidence assessment, appraisal, and recommendation. The Excel-based tool guides the user through the steps and document discussions in a transparent manner, with an emphasis on stakeholder engagement and country ownership. Conclusions: Pilot countries valued the CAPACITI decision-support tool as a means to consider multiple criteria and stakeholder perspectives and to evaluate trade-offs and the impact of data quality. With use, it is expected that LMICs will tailor steps to their context and streamline the tool for decision making.The impact of childhood pneumococcal conjugate vaccine immunisation on all-cause pneumonia admissions in Hong Kong : A 14-year population-based interrupted time series analysis
AbstractYu, Q., Li, X., Fan, M., Qiu, H., Wong, A. Y., Tian, L., Chui, C. S., Li, P. H., Lau, L. K., Chan, E. W., Goggins, W. B., Ip, P., Lum, T. Y., Hung, I. F., Cowling, B. J., Wong, I. C., & Jit, M. (n.d.).Publication year
2021Journal title
VaccineVolume
39Issue
19Page(s)
2628-2635AbstractBackground: Nine years after the introduction of pneumococcal conjugate vaccine (PCV) in the United States, Hong Kong (HK) introduced the vaccine to its universal childhood immunisation programme in 2009. We aimed to assess the impact of childhood PCV immunisation on all-cause pneumonia (ACP) admissions among the overall population of HK. Methods: In this population-based interrupted time series analysis, we used territory-wide population-representative electronic health records in HK to evaluate the vaccine impact. We identified hospitalised patients with a diagnosis of pneumonia from any cause between 2004 and 2017. We applied segmented Poisson regression to assess the gradual change in the monthly incidence of ACP admissions between pre- and post-vaccination periods. Negative outcome control, subgroup and sensitivity analyses were used to test the robustness of the main analysis. Findings: Over the 14-year study period, a total of 587,607 ACP episodes were identified among 357,950 patients. The monthly age-standardised incidence of ACP fluctuated between 33.42 and 87.44 per 100,000-persons. There was a marginal decreasing trend in pneumonia admissions after PCV introduction among overall population (incidence rate ratio [IRR]: 0·9965, 95% confidence interval [CI]: 0·9932–0·9998), and older adults (≥65 years, IRR: 0·9928, 95% CI: 0·9904–0·9953) but not in younger age groups. Interpretation: There was a marginally declining trend of overall ACP admissions in HK up to eight years after childhood PCV introduction. The significance disappeared when fitting sensitivity analyses. The results indicate the complexities of using non-specific endpoints for measuring vaccine effect and the necessity of enhancing serotype surveillance systems for replacement monitoring. Funding: Health and Medical Research Fund, Food and Health Bureau of the Government of Hong Kong (Reference number: 18171272).The impact of local and national restrictions in response to COVID-19 on social contacts in England : a longitudinal natural experiment
AbstractCMMID COVID-19 Working Group, A., Jarvis, C. I., Gimma, A., van Zandvoort, K., Wong, K. L., Abbas, K., Villabona-Arenas, C. J., O’Reilly, K., Quaife, M., Rosello, A., Kucharski, A. J., Gibbs, H. P., Atkins, K. E., Barnard, R. C., Bosse, N. I., Procter, S. R., Meakin, S. R., Sun, F. Y., Abbott, S., … Klepac, P. (n.d.).Publication year
2021Journal title
BMC MedicineVolume
19Issue
1AbstractBackground: England’s COVID-19 response transitioned from a national lockdown to localised interventions. In response to rising cases, these were supplemented by national restrictions on contacts (the Rule of Six), then 10 pm closing for bars and restaurants, and encouragement to work from home. These were quickly followed by a 3-tier system applying different restrictions in different localities. As cases continued to rise, a second national lockdown was declared. We used a national survey to quantify the impact of these restrictions on epidemiologically relevant contacts. Methods: We compared paired measures on setting-specific contacts before and after each restriction started and tested for differences using paired permutation tests on the mean change in contacts and the proportion of individuals decreasing their contacts. Results: Following the imposition of each measure, individuals tended to report fewer contacts than they had before. However, the magnitude of the changes was relatively small and variable. For instance, although early closure of bars and restaurants appeared to have no measurable effect on contacts, the work from home directive reduced mean daily work contacts by 0.99 (95% confidence interval CI] 0.03–1.94), and the Rule of Six reduced non-work and school contacts by a mean of 0.25 (0.01–0.5) per day. Whilst Tier 3 appeared to also reduce non-work and school contacts, the evidence for an effect of the lesser restrictions (Tiers 1 and 2) was much weaker. There may also have been some evidence of saturation of effects, with those who were in Tier 1 (least restrictive) reducing their contacts markedly when they entered lockdown, which was not reflected in similar changes in those who were already under tighter restrictions (Tiers 2 and 3). Conclusions: The imposition of various local and national measures in England during the summer and autumn of 2020 has gradually reduced contacts. However, these changes are smaller than the initial lockdown in March. This may partly be because many individuals were already starting from a lower number of contacts.The impact of non-pharmaceutical interventions on SARS-CoV-2 transmission across 130 countries and territories
AbstractCMMID COVID-19 Working Group, A., Liu, Y., Morgenstern, C., Kelly, J., Lowe, R., Munday, J., Villabona-Arenas, C. J., Gibbs, H., Pearson, C. A., Prem, K., Leclerc, Q. J., Meakin, S. R., Edmunds, W. J., Jarvis, C. I., Gimma, A., Funk, S., Quaife, M., Russell, T. W., Emory, J. C., … Jit, M. (n.d.).Publication year
2021Journal title
BMC MedicineVolume
19Issue
1AbstractBackground: Non-pharmaceutical interventions (NPIs) are used to reduce transmission of SARS coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). However, empirical evidence of the effectiveness of specific NPIs has been inconsistent. We assessed the effectiveness of NPIs around internal containment and closure, international travel restrictions, economic measures, and health system actions on SARS-CoV-2 transmission in 130 countries and territories. Methods: We used panel (longitudinal) regression to estimate the effectiveness of 13 categories of NPIs in reducing SARS-CoV-2 transmission using data from January to June 2020. First, we examined the temporal association between NPIs using hierarchical cluster analyses. We then regressed the time-varying reproduction number (Rt) of COVID-19 against different NPIs. We examined different model specifications to account for the temporal lag between NPIs and changes in Rt, levels of NPI intensity, time-varying changes in NPI effect, and variable selection criteria. Results were interpreted taking into account both the range of model specifications and temporal clustering of NPIs. Results: There was strong evidence for an association between two NPIs (school closure, internal movement restrictions) and reduced Rt. Another three NPIs (workplace closure, income support, and debt/contract relief) had strong evidence of effectiveness when ignoring their level of intensity, while two NPIs (public events cancellation, restriction on gatherings) had strong evidence of their effectiveness only when evaluating their implementation at maximum capacity (e.g. restrictions on 1000+ people gathering were not effective, restrictions on < 10 people gathering were). Evidence about the effectiveness of the remaining NPIs (stay-at-home requirements, public information campaigns, public transport closure, international travel controls, testing, contact tracing) was inconsistent and inconclusive. We found temporal clustering between many of the NPIs. Effect sizes varied depending on whether or not we included data after peak NPI intensity. Conclusion: Understanding the impact that specific NPIs have had on SARS-CoV-2 transmission is complicated by temporal clustering, time-dependent variation in effects, and differences in NPI intensity. However, the effectiveness of school closure and internal movement restrictions appears robust across different model specifications, with some evidence that other NPIs may also be effective under particular conditions. This provides empirical evidence for the potential effectiveness of many, although not all, actions policy-makers are taking to respond to the COVID-19 pandemic.The importance of saturating density dependence for population-level predictions of SARS-CoV-2 resurgence compared with density-independent or linearly density-dependent models, England, 23 March to 31 July 2020
AbstractCMMID COVID-19 Working Group, A., Nightingale, E. S., Brady, O. J., Yakob, L., Gimma, A., Jit, M., Jarvis, C. I., Waterlow, N. R., Procter, S. R., Auzenbergs, M., Tully, D. C., Simons, D., Endo, A., Hellewell, J., Lowe, R., Foss, A. M., van Zandvoort, K., Pearson, C. A., Showering, A., … Clifford, S. (n.d.).Publication year
2021Journal title
EurosurveillanceVolume
26Issue
49AbstractBackground: Population-level mathematical models of outbreaks typically assume that disease transmission is not impacted by population density (‘frequency-dependent’) or that it increases linearly with density (‘density-dependent’). Aim: We sought evidence for the role of population density in SARS-CoV-2 transmission. Methods: Using COVID-19-associated mortality data from England, we fitted multiple functional forms linking density with transmission. We projected forwards beyond lockdown to ascertain the consequences of different functional forms on infection resurgence. Results: COVID-19-associated mortality data from England show evidence of increasing with population density until a saturating level, after adjusting for local age distribution, deprivation, proportion of ethnic minority population and proportion of key workers among the working population. Projections from a mathematical model that accounts for this observation deviate markedly from the current status quo for SARS-CoV-2 models which either assume linearity between density and transmission (30% of models) or no relationship at all (70%). Respectively, these classical model structures over- and underestimate the delay in infection resurgence following the release of lockdown. Conclusion: Identifying saturation points for given populations and including transmission terms that account for this feature will improve model accuracy and utility for the current and future pandemics.The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya
AbstractLSHTM CMMID COVID-19 Working Group, A., Mburu, C. N., Ojal, J., Chebet, R., Akech, D., Karia, B., Tuju, J., Sigilai, A., Abbas, K., Jit, M., Funk, S., Smits, G., van Gageldonk, P. G., van der Klis, F. R., Tabu, C., Nokes, D. J., Munday, J. D., Pearson, C. A., Procter, S. R., … Jit, M. (n.d.).Publication year
2021Journal title
BMC MedicineVolume
19Issue
1AbstractBackground: The COVID-19 pandemic has disrupted routine measles immunisation and supplementary immunisation activities (SIAs) in most countries including Kenya. We assessed the risk of measles outbreaks during the pandemic in Kenya as a case study for the African Region. Methods: Combining measles serological data, local contact patterns, and vaccination coverage into a cohort model, we predicted the age-adjusted population immunity in Kenya and estimated the probability of outbreaks when contact-reducing COVID-19 interventions are lifted. We considered various scenarios for reduced measles vaccination coverage from April 2020. Results: In February 2020, when a scheduled SIA was postponed, population immunity was close to the herd immunity threshold and the probability of a large outbreak was 34% (8–54). As the COVID-19 contact restrictions are nearly fully eased, from December 2020, the probability of a large measles outbreak will increase to 38% (19–54), 46% (30–59), and 54% (43–64) assuming a 15%, 50%, and 100% reduction in measles vaccination coverage. By December 2021, this risk increases further to 43% (25–56), 54% (43–63), and 67% (59–72) for the same coverage scenarios respectively. However, the increased risk of a measles outbreak following the lifting of all restrictions can be overcome by conducting a SIA with ≥ 95% coverage in under-fives. Conclusion: While contact restrictions sufficient for SAR-CoV-2 control temporarily reduce measles transmissibility and the risk of an outbreak from a measles immunity gap, this risk rises rapidly once these restrictions are lifted. Implementing delayed SIAs will be critical for prevention of measles outbreaks given the roll-back of contact restrictions in Kenya.