Mark Jit

Chair and Professor of the Department of Global and Environmental Health

Professional overview

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.

Education

BSc, Mathematics, University College London

PhD, Mathematics, University College London

MPH, Public Health, King's College London

Honors and awards

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)

Publications

Publications

Economic analyses to support decisions about HPV vaccination in low- and middle-income countries : A consensus report and guide for analysts

Jit, M., Levin, C., Brisson, M., Levin, A., Resch, S., Berkhof, J., Kim, J., & Hutubessy, R. (n.d.).

Publication year

2013

Journal title

BMC Medicine

Volume

11

Issue

1

10.1186/1741-7015-11-23

Abstract

Abstract

Low- and middle-income countries need to consider economic issues such as cost-effectiveness, affordability and sustainability before introducing a program for human papillomavirus (HPV) vaccination. However, many such countries lack the technical capacity and data to conduct their own analyses. Analysts informing policy decisions should address the following questions: 1) Is an economic analysis needed? 2) Should analyses address costs, epidemiological outcomes, or both? 3) If costs are considered, what sort of analysis is needed? 4) If outcomes are considered, what sort of model should be used? 5) How complex should the analysis be? 6) How should uncertainty be captured? 7) How should model results be communicated? Selecting the appropriate analysis is essential to ensure that all the important features of the decision problem are correctly represented, but that the analyses are not more complex than necessary. This report describes the consensus of an expert group convened by the World Health Organization, prioritizing key issues to be addressed when considering economic analyses to support HPV vaccine introduction in these countries.

Efficacy and effectiveness of seasonal and pandemic A (H1N1) 2009 influenza vaccines in low and middle income countries : A systematic review and meta-analysis

Breteler, J. K., Tam, J. S., Jit, M., Ket, J. C., & De Boer, M. R. (n.d.).

Publication year

2013

Journal title

Vaccine

Volume

31

Issue

45

Page(s)

5168-5177

10.1016/j.vaccine.2013.08.056

Abstract

Abstract

Purpose: Influenza vaccines have been recommended for populations at risk for severe infection in low and middle income countries (LMICs) although knowledge of the evidence-base for their effectiveness and efficacy is limited in these countries. The aim of this systematic review is to provide an overview of the evidence-base for the effectiveness and efficacy of influenza vaccines in LMICs and to explore critical knowledge gaps. Methods: PubMed, EMBASE, and Cochrane were searched for seasonal and pandemic A (H1N1) 2009 influenza vaccine effectiveness and efficacy studies performed in LMICs. Eligible studies included RCTs and observational studies, published in English, French, Spanish or Portuguese between 1960 and 2011, which assessed laboratory-confirmed influenza and/or influenza-related outcomes in any population. Risk of bias was assessed by two reviewers independently. Random effects pooled estimates were obtained when sufficient data were available. Results: A total of 6465 articles were screened. Forty-one studies were included on seasonal influenza vaccine effectiveness and efficacy and one study on pandemic vaccine effectiveness. In middle income countries (MICs), efficacy of seasonal influenza vaccines was shown against laboratory-confirmed influenza in children (pooled efficacy 72% (95%CI: 65-77) and 81% (95%CI: 69-89), for one and two years follow-up respectively) and in the elderly (pooled efficacy 43% (95%CI: 25-56) and 58% (95%CI: 23-78), for live attenuated and inactivated vaccine respectively). Inactivated influenza vaccines were also found to be effective against cardiovascular outcomes in patients with coronary syndromes. Conclusions: Seasonal influenza vaccines can provide protection in children, the elderly and patients with coronary syndromes in MICs, and seem to be equally effective as compared to high income countries. Data for other high risk groups and from low income countries were limited or prone to bias, and are needed to further facilitate evidence-based decision making regarding influenza vaccination in LMICs.

Influenza vaccines in low and middle income countries : A systematic review of economic evaluations

Ott, J. J., Breteler, J. K., Tam, J. S., Hutubessy, R. C., Jit, M., & De Boer, M. R. (n.d.).

Publication year

2013

Journal title

Human Vaccines and Immunotherapeutics

Volume

9

Issue

7

Page(s)

1500-1511

10.4161/hv.24704

Abstract

Abstract

Objectives: Economic evaluations on influenza vaccination from low resource settings are scarce and have not been evaluated using a systematic approach. Our objective was to conduct a systematic review on the value for money of influenza vaccination in low- and middle-income countries. Methods: PubMed and EMBASE were searched for economic evaluations published in any language between 1960 and 2011. Main outcome measures were costs per influenza outcome averted, costs per quality-adjusted life years gained or disability-adjusted life years averted, costs per benefit in monetary units or cost-benefit ratios. Results: Nine economic evaluations on seasonal influenza vaccine met the inclusion criteria. These were model- or randomized-controlled-trial (RCT)-based economic evaluations from middle-income countries. Influenza vaccination provided value for money for elderly, infants, adults and children with high-risk conditions. Vaccination was cost-effective and costsaving for chronic obstructive pulmonary disease patients and in elderly above 65 y from model-based evaluations, but conclusions from RCTs on elderly varied. Conclusion: Economic evaluations from middle income regions differed in population studied, outcomes and definitions used. Most findings are in line with evidence from high-income countries highlighting that influenza vaccine is likely to provide value for money. However, serious methodological limitations do not allow drawing conclusions on cost-effectiveness of influenza vaccination in middle income countries. Evidence on cost-effectiveness from low-income countries is lacking altogether, and more information is needed from full economic evaluations that are conducted in a standardized manner.

Key issues for estimating the impact and cost-effectiveness of seasonal influenza vaccination strategies

Jit, M., Newall, A. T., & Beutels, P. (n.d.).

Publication year

2013

Journal title

Human Vaccines and Immunotherapeutics

Volume

9

Issue

4

Page(s)

834-840

10.4161/hv.23637

Abstract

Abstract

Many countries have considered or are considering modifying their seasonal influenza immunization policies. Estimating the impact of such changes requires understanding the existing clinical and economic burden of influenza, as well as the potential impact of different vaccination options. Previous studies suggest that vaccinating clinical risk groups, health care workers, children and the elderly may be cost-effective. However, challenges in such estimation include: (1) potential cases are not usually virologically tested; (2) cases have nonspecific symptoms and are rarely reported to surveillance systems; (3) endpoints for influenza proxies (such as influenzalike illness) need to be matched to case definitions for treatment costs, (4) disease burden estimates vary from year to year with strain transmissibility, virulence and prior immunity, (5) methods to estimate productivity losses due to influenza vary, (6) vaccine efficacy estimates from trials differ due to variation in subtype prevalence, vaccine match and case ascertainment, and (7) indirect (herd) protection from vaccination depends on settingspecific variables that are difficult to directly measure. Given the importance of knowing the impact of changes to influenza policy, such complexities need careful treatment using tools such as population-based trial designs, meta-analyses, timeseries analyses and transmission dynamic models.

Modelling the transmission of healthcare associated infections : A systematic review

van Kleef, E., Robotham, J. V., Jit, M., Deeny, S. R., & Edmunds, W. J. (n.d.).

Publication year

2013

Journal title

BMC Infectious Diseases

Volume

13

Issue

1

10.1186/1471-2334-13-294

Abstract

Abstract

Background: Dynamic transmission models are increasingly being used to improve our understanding of the epidemiology of healthcare-associated infections (HCAI). However, there has been no recent comprehensive review of this emerging field. This paper summarises how mathematical models have informed the field of HCAI and how methods have developed over time.Methods: MEDLINE, EMBASE, Scopus, CINAHL plus and Global Health databases were systematically searched for dynamic mathematical models of HCAI transmission and/or the dynamics of antimicrobial resistance in healthcare settings.Results: In total, 96 papers met the eligibility criteria. The main research themes considered were evaluation of infection control effectiveness (64%), variability in transmission routes (7%), the impact of movement patterns between healthcare institutes (5%), the development of antimicrobial resistance (3%), and strain competitiveness or co-colonisation with different strains (3%). Methicillin-resistant Staphylococcus aureus was the most commonly modelled HCAI (34%), followed by vancomycin resistant enterococci (16%). Other common HCAIs, e.g. Clostridum difficile, were rarely investigated (3%). Very few models have been published on HCAI from low or middle-income countries.The first HCAI model has looked at antimicrobial resistance in hospital settings using compartmental deterministic approaches. Stochastic models (which include the role of chance in the transmission process) are becoming increasingly common. Model calibration (inference of unknown parameters by fitting models to data) and sensitivity analysis are comparatively uncommon, occurring in 35% and 36% of studies respectively, but their application is increasing. Only 5% of models compared their predictions to external data.Conclusions: Transmission models have been used to understand complex systems and to predict the impact of control policies. Methods have generally improved, with an increased use of stochastic models, and more advanced methods for formal model fitting and sensitivity analyses. Insights gained from these models could be broadened to a wider range of pathogens and settings. Improvements in the availability of data and statistical methods could enhance the predictive ability of models.

Reduction in HPV 16/18 prevalence in sexually active young women following the introduction of HPV immunisation in England

Jit, M., Mesher, D., Soldan, K., Howell-Jones, R., Panwar, K., Manyenga, P., Jit, M., Beddows, S., & Gill, O. N. (n.d.).

Publication year

2013

Journal title

Vaccine

Volume

32

Issue

1

Page(s)

26-32

10.1016/j.vaccine.2013.10.085

Abstract

Abstract

Background: Reduction in the prevalence of vaccine type HPV infection in young women is an early indication of the impact of the HPV immunisation programme and a necessary outcome if the subsequent impact on cervical cancer is to be realised. Methods: Residual vulva-vaginal swab (VVS) specimens from young women aged 16-24 years undergoing chlamydia screening in community sexual health services (formerly known as family planning clinics), general practice (GP), and youth clinics in 2010-2012 were submitted from 10 laboratories in seven regions around England. These specimens were linked to demographic and sexual behaviour data reported with the chlamydia test, anonymised, and tested for type-specific HPV DNA using a multiplex PCR and Luminex-based genotyping test. Estimated immunisation coverage was calculated and findings were compared to a baseline survey conducted prior to the introduction of HPV immunisation in 2008. Results: A total of 4664 eligible specimens were collected and 4178 had a valid test result. The post-immunisation prevalence of HPV 16/18 infection was lowest in this youngest age group (16-18 years) and increased with age. This increase with age was a reversal of the pattern seen prior to immunisation and was inversely associated with estimates of age-specific immunisation coverage (65% for 16-18 year olds). The prevalence of HPV 16/18 infection in the post-immunisation survey was 6.5% amongst 16-18 year olds, compared to 19.1% in the similar survey conducted prior to the introduction of HPV immunisation. Conclusions: These findings are the first indication that the national HPV immunisation programme is successfully preventing HPV 16/18 infection in sexually active young women in England. The reductions seen suggest, for the estimated coverage, high vaccine effectiveness and some herd-protection benefits. Continued surveillance is needed to determine the effects of immunisation on non-vaccine HPV types.

Trends in parameterization, economics and host behaviour in influenza pandemic modelling : A review and reporting protocol

Carrasco, L. R., Jit, M., Chen, M. I., Lee, V. J., Milne, G. J., & Cook, A. R. (n.d.).

Publication year

2013

Journal title

Emerging Themes in Epidemiology

Volume

10

Issue

1

10.1186/1742-7622-10-3

Abstract

Abstract

Background: The volume of influenza pandemic modelling studies has increased dramatically in the last decade. Many models incorporate now sophisticated parameterization and validation techniques, economic analyses and the behaviour of individuals. Methods. We reviewed trends in these aspects in models for influenza pandemic preparedness that aimed to generate policy insights for epidemic management and were published from 2000 to September 2011, i.e. before and after the 2009 pandemic. Results: We find that many influenza pandemics models rely on parameters from previous modelling studies, models are rarely validated using observed data and are seldom applied to low-income countries. Mechanisms for international data sharing would be necessary to facilitate a wider adoption of model validation. The variety of modelling decisions makes it difficult to compare and evaluate models systematically. Conclusions: We propose a model Characteristics, Construction, Parameterization and Validation aspects protocol (CCPV protocol) to contribute to the systematisation of the reporting of models with an emphasis on the incorporation of economic aspects and host behaviour. Model reporting, as already exists in many other fields of modelling, would increase confidence in model results, and transparency in their assessment and comparison.

Use of measles supplemental immunization activities (SIAs) as a delivery platform for other maternal and child health interventions : Opportunities and challenges

Johri, M., Sharma, J. K., Jit, M., & Verguet, S. (n.d.).

Publication year

2013

Journal title

Vaccine

Volume

31

Issue

9

Page(s)

1259-1263

10.1016/j.vaccine.2012.09.044

Abstract

Abstract

Measles supplementary immunization activities (SIAs) offer children in countries with weaker immunization delivery systems like India a second opportunity for measles vaccination. They could also provide a platform to deliver additional interventions, but the feasibility and acceptability of including add-ons is uncertain. We surveyed Indian programme officers involved in the current (2010-2012) measles SIAs concerning opportunities and challenges of using SIAs as a delivery platform for other maternal and child health interventions. Respondents felt that an expanded SIA strategy including add-ons could be of great value in improving access and efficiency. They viewed management challenges, logistics, and safety as the most important potential barriers. They proposed that additional interventions be selected using several criteria, of which importance of the health problem, safety, and contribution to health equity figured most prominently. For children, they recommended inclusion of basic interventions to address nutritional deficiencies, diarrhoea and parasites over vaccines. For mothers, micronutrient interventions were highest ranked.

Cross-protective efficacy of two human papillomavirus vaccines : A systematic review and meta-analysis

Malagón, T., Drolet, M., Boily, M. C., Franco, E. L., Jit, M., Brisson, J., & Brisson, M. (n.d.).

Publication year

2012

Journal title

The Lancet Infectious Diseases

Volume

12

Issue

10

Page(s)

781-789

10.1016/S1473-3099(12)70187-1

Abstract

Abstract

Background: The extent of cross-protection is a key element in the choice of human papillomavirus (HPV) vaccine to use in vaccination programmes. We compared the cross-protective efficacy of the bivalent vaccine (HPV 16 and 18; Cervarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) and quadrivalent vaccine (HPV 6, 11, 16, and 18; Gardasil, Merck, Whitehouse Station, NJ, USA) against non-vaccine type HPVs. Methods: We searched Medline and Embase databases, conference abstracts, and manufacturers' websites for randomised clinical trials assessing the efficacy of bivalent and quadrivalent vaccines against persistent infections (lasting ≥6 months) and cervical intraepithelial neoplasia (CIN) associated with the non-vaccine type HPVs (types 31, 33, 45, 52, and 58). We included studies of participants who were HPV DNA negative before vaccination for all HPV types assessed. We assessed heterogeneity in vaccine efficacy estimates between trials with I2 and χ2 statistics. Findings: We identified two clinical trials (Females United to Unilaterally Reduce Endo/Ectocervical Disease [FUTURE] I and II) of the quadrivalent vaccine and three (Papilloma Trial Against Cancer In Young Adults [PATRICIA], HPV007, and HPV-023) of the bivalent vaccine. Analysis of the most comparable populations (pooled FUTURE I/II data vs PATRICIA) suggested that cross-protective vaccine efficacy estimates against infections and lesions associated with HPV 31, 33, and 45 were usually higher for the bivalent vaccine than the quadrivalent vaccine. Vaccine efficacy in the bivalent trial was higher than it was in the quadrivalent trial against persistent infections with HPV 31 (77·1% [95% CI 67·2 to 84·4] for bivalent vaccine vs 46·2% [15·3 to 66·4] for quadrivalent vaccine; p=0·003) and HPV 45 (79·0% [61·3 to 89·4] vs 7·8% [-67·0 to 49·3]; p=0·0003), and against CIN grade 2 or worse associated with HPV 33 (82·3% [53·4 to 94·7] vs 24·0% [-71·2 to 67·2]; p=0·02) and HPV 45 (100% [41·7 to 100] vs -51·9% [-1717·8 to 82·6]; p=0·04). We noted substantial heterogeneity between vaccine efficacy in bivalent trials against persistent infections with HPV 31 (I2=69%, p=0·04) and HPV 45 (I2=70%, p=0·04), with apparent reductions in cross-protective efficacy with increased follow-up. Interpretation: The bivalent vaccine seems more efficacious against non-vaccine HPV types 31, 33, and 45 than the quadrivalent vaccine, but the differences were not all significant and might be attributable to differences in trial design. Efficacy against persistent infections with types 31 and 45 seemed to decrease in bivalent trials with increased follow-up, suggesting a waning of cross-protection; more data are needed to establish duration of cross-protection. Funding: Public Health Agency of Canada.

Economic evaluations of childhood influenza vaccination : A critical review

Newall, A. T., Jit, M., & Beutels, P. (n.d.).

Publication year

2012

Journal title

PharmacoEconomics

Volume

30

Issue

8

Page(s)

647-660

10.2165/11599130-000000000-00000

Abstract

Abstract

The potential benefits of influenza vaccination programmes targeted at children have gained increasing attention in recent years.We conducted a literature search of economic evaluations of influenza vaccination in those aged ≤18 years. The search revealed 20 relevant articles, which were reviewed. The studies differed widely in terms of the costs and benefits that were included. The conclusions were generally favourable for vaccination, but often applied a wider perspective (i.e. including productivity losses) than the reference case for economic evaluations used in many countries. Several evaluations estimated outcomes from a single-year epidemiological study, which may limit their validity given the year-to-year variation in influenza transmissibility, virulence, vaccine match and prior immunity. Only one study used a dynamic transmission model able to fully incorporate the indirect herd protection to the wider community.The use of dynamic models offers great scope to capture the population-wide implications of seasonal vaccination efforts, particularly those targeted at children. Adis

Enzymes provide demographers with food for thought

Jit, M., & Gerland, P. (n.d.).

Publication year

2012

Journal title

eLife

Volume

2012

Issue

1

10.7554/eLife.00340

Abstract

Abstract

~

Health and economic impact of the seasonal influenza vaccination programme in England

Baguelin, M., Jit, M., Miller, E. A., & Edmunds, W. J. (n.d.).

Publication year

2012

Journal title

Vaccine

Volume

30

Issue

23

Page(s)

3459-3462

10.1016/j.vaccine.2012.03.019

Abstract

Abstract

Background: The seasonal influenza vaccination programme in England targets individuals over 65. years old and in clinical risk groups. Methods: A model of influenza transmission and disease was fitted to weekly primary care consultations due to influenza in a typical pre-pandemic season (2006/2007). Different scenarios were constructed about influenza severity and how well vaccines match circulating strains to assess the impact and cost-effectiveness of the current vaccination programme. Results: A well-matched vaccine may reduce the incidence of laboratory-confirmed influenza illness from 8.2% (95% range 4.3-13%) to 5.9% (95% range 2.9-9.7%), with 56-73% of this due to indirect protection. The programme is likely to be cost-effective unless both low severity and poor matching is assumed. Conclusion: The current seasonal influenza vaccination programme appears to substantially reduce disease burden and provides good value for money.

Mathematical modelling long-term effects of replacing prevnar7 with prevnar13 on invasive pneumococcal diseases in england and wales

Choi, Y. H., Jit, M., Flasche, S., Gay, N., & Miller, E. A. (n.d.).

Publication year

2012

Journal title

PloS one

Volume

7

Issue

7

10.1371/journal.pone.0039927

Abstract

Abstract

Introduction: England and Wales recently replaced the 7-valent pneumococcal conjugate vaccine (PCV7) with its 13-valent equivalent (PCV13), partly based on projections from mathematical models of the long-term impact of such a switch compared to ceasing pneumococcal conjugate vaccination altogether. Methods: A compartmental deterministic model was used to estimate parameters governing transmission of infection and competition between different groups of pneumococcal serotypes prior to the introduction of PCV13. The best-fitting parameters were used in an individual based model to describe pneumococcal transmission dynamics and effects of various options for the vaccination programme change in England and Wales. A number of scenarios were conducted using (i) different assumptions about the number of invasive pneumococcal disease cases adjusted for the increasing trend in disease incidence prior to PCV7 introduction in England and Wales, and (ii) a range of values representing serotype replacement induced by vaccination of the additional six serotypes in PCV13. Results: Most of the scenarios considered suggest that ceasing pneumococcal conjugate vaccine use would cause an increase in invasive pneumococcal disease incidence, while replacing PCV7 with PCV13 would cause an overall decrease. However, the size of this reduction largely depends on the level of competition induced by the additional serotypes in PCV13. The model estimates that over 20 years of PCV13 vaccination, around 5000-62000 IPD cases could be prevented compared to stopping pneumococcal conjugate vaccination altogether. Conclusion: Despite inevitable uncertainty around serotype replacement effects following introduction of PCV13, the model suggests a reduction in overall invasive pneumococcal disease incidence in all cases. Our results provide useful evidence on the benefits of PCV13 to countries replacing or considering replacing PCV7 with PCV13, as well as data that can be used to evaluate the cost-effectiveness of such a switch.

Potential overestimation of HPV vaccine impact due to unmasking of non-vaccine types : Quantification using a multi-type mathematical model

Choi, Y. H., Chapman, R., Gay, N., & Jit, M. (n.d.).

Publication year

2012

Journal title

Vaccine

Volume

30

Issue

23

Page(s)

3383-3388

10.1016/j.vaccine.2012.03.065

Abstract

Abstract

Introduction: Estimates of human papillomavirus (HPV) vaccine impact in clinical trials and modelling studies rely on DNA tests of cytology or biopsy specimens to determine the HPV type responsible for a cervical lesion. DNA of several oncogenic HPV types may be detectable in a specimen. However, only one type may be responsible for a particular cervical lesion. Misattribution of the causal HPV type for a particular abnormality may give rise to an apparent increase in disease due to non-vaccine HPV types following vaccination (" unmasking" ). Methods: To investigate the existence and magnitude of unmasking, we analysed data from residual cytology and biopsy specimens in English women aged 20-64 years old using a stochastic type-specific individual-based model of HPV infection, progression and disease. The model parameters were calibrated to data on the prevalence of HPV DNA and cytological lesion of different grades, and used to assign causal HPV types to cervical lesions. The difference between the prevalence of all disease due to non-vaccine HPV types, and disease due to non-vaccine HPV types in the absence of vaccine HPV types, was then estimated. Results: There could be an apparent maximum increase of 3-10% in long-term cervical cancer incidence due to non-vaccine HPV types following vaccination. Conclusion: Unmasking may be an important phenomenon in HPV post-vaccination epidemiology, in the same way that has been observed following pneumococcal conjugate vaccination.

Systematic review of studies evaluating the broader economic impact of vaccination in low and middle income countries

Deogaonkar, R., Hutubessy, R., Van Der Putten, I., Evers, S., & Jit, M. (n.d.).

Publication year

2012

Journal title

BMC public health

Volume

12

Issue

1

10.1186/1471-2458-12-878

Abstract

Abstract

Background: Most health economic evaluations of childhood vaccination only capture the health and short-term economic benefits. Measuring broader, long-term effects of vaccination on productivity and externalities could provide a more complete picture of the value of vaccines. Method. MEDLINE, EconLit and NHS-EED databases were searched for articles published between January 1990 and July 2011, which captured broader economic benefits of vaccines in low and middle income countries. Studies were included if they captured at least one of the following categories on broader economic impact: outcome-related productivity gains, behaviour-related productivity gains, ecological externalities, equity gains, financial sustainability gains or macroeconomic benefits. Results: Twenty-six relevant studies were found, including observational studies, economic models and contingent valuation studies. Of the identified broader impacts, outcome-related productivity gains and ecological externalities were most commonly accounted for. No studies captured behaviour-related productivity gains or macroeconomic effects. There was some evidence to show that vaccinated children 8-14 years of age benefit from increased cognitive ability. Productivity loss due to morbidity and mortality was generally measured using the human capital approach. When included, herd immunity effects were functions of coverage rates or based on reduction in disease outcomes. External effects of vaccines were observed in terms of equitable health outcomes and contribution towards synergistic and financially sustainable healthcare programs. Conclusion: Despite substantial variation in the methods of measurement and outcomes used, the inclusion of broader economic impact was found to improve the attractiveness of vaccination. Further research is needed on how different tools and techniques can be used in combination to capture the broader impact of vaccination in a way that is consistent with other health economic evaluations. In addition, more country level evidence is needed from low and middle income countries to justify future investments in vaccines and immunization programs. Finally, the proposed broader economic impact framework may contribute towards better communication of the economic arguments surrounding vaccine uptake, leading to investments in immunization by stakeholders outside of the traditional health care sector such as ministries of finance and national treasuries.

The cost-effectiveness of a 13-valent pneumococcal conjugate vaccination for infants in England

van Hoek, A. J., Choi, Y. H., Trotter, C., Miller, E. A., & Jit, M. (n.d.).

Publication year

2012

Journal title

Vaccine

Volume

30

Issue

50

Page(s)

7205-7213

10.1016/j.vaccine.2012.10.017

Abstract

Abstract

Background: In the immunisation schedule in England and Wales, the 7-valent pneumococcal conjugate vaccine (PCV-7) was replaced by the 13-valent vaccine (PCV-13) in April 2010 after having been used since September 2006. The introduction of PCV-7 was informed by a cost effectiveness analysis using an infectious disease model which projected herd immunity and serotype replacement effects based on the post-vaccine experience in the United States at that time. Aim: To investigate the cost effectiveness of the introduction of PCV-13. Method: Invasive disease incidence following vaccination was projected from a dynamic infectious disease model, and combined with serotype specific disease outcomes obtained from a large hospital dataset linked to laboratory confirmation of invasive pneumococcal disease. The economic impact of replacing PCV-7 with PCV-13 was compared to stopping the use of pneumococcal conjugate vaccination altogether. Results: Discontinuing PCV-7 would lead to a projected increase in invasive pneumococcal disease, costs and loss of quality of life compared to the introduction of PCV-13. However under base case assumptions (assuming no impact on non-invasive disease, maximal competition between vaccine and non-vaccine types, time horizon of 30. years, vaccine price of £49.60 a dose. +. £7.50 administration costs and discounting of costs and benefits at 3.5%) the introduction of PCV-13 is only borderline cost effective compared to a scenario of discontinuing of PCV-7. The intervention becomes more cost-effective when projected impact of non-invasive disease is included or the discount factor for benefits is reduced to 1.5%. Conclusion: To our knowledge this is the first evaluation of a transition from PCV-7 to PCV-13 based on a dynamic model. The cost-effectiveness of such a policy change depends on a number of crucial assumptions for which evidence is limited, particularly the impact of PCV-13 on non-invasive disease.

7-valent pneumococcal conjugate vaccination in england and wales : Is it still beneficial despite high levels of serotype replacement?

Choi, Y. H., Jit, M., Gay, N., Andrews, N., Waight, P. A., Melegaro, A., George, R., & Miller, E. A. (n.d.).

Publication year

2011

Journal title

PloS one

Volume

6

Issue

10

10.1371/journal.pone.0026190

Abstract

Abstract

Background: The UK introduced the 7-valent pneumococcal conjugate vaccine (PCV7) into the national vaccination program in September 2006. Previous modelling assumed that the likely impact of PCV7 on invasive pneumococcal disease (IPD) would be similar to the US experience with PCV7. However, recent surveillance data show a more rapid replacement of PCV7 IPD cases by non-PCV7 IPD cases than was seen in the US. Methods and Findings: A previous model of pneumococcal vaccination was re-parameterised using data on vaccine coverage and IPD from England and Wales between 2006 and 2009. Disease incidence was adjusted for the increasing trend in reported IPD cases prior to vaccination. Using this data we estimated that individuals carrying PCV7 serotypes have much higher protection (96%;95% CI 72%-100%) against acquisition of NVT carriage than the 15% previously estimated from US data, which leads to greater replacement. However, even with this level of replacement, the annual number of IPD cases may be 560 (95% CI, -100 to 1230) lower ten years after vaccine introduction compared to what it may have been without vaccination. A particularly marked fall of 39% in children under 15 years by 2015/6 is predicted. Conclusion: Our model suggests that PCV7 vaccination could result in a decrease in overall invasive pneumococcal disease, particularly in children, even in an environment of rapid replacement with non-PCV7 serotypes within 5 years of vaccine introduction at high coverage.

Accounting for methodological, structural, and parameter uncertainty in decision-analytic models : A practical guide

Bilcke, J., Beutels, P., Brisson, M., & Jit, M. (n.d.).

Publication year

2011

Journal title

Medical Decision Making

Volume

31

Issue

4

Page(s)

675-692

10.1177/0272989X11409240

Abstract

Abstract

Accounting for uncertainty is now a standard part of decision-analytic modeling and is recommended by many health technology agencies and published guidelines. However, the scope of such analyses is often limited, even though techniques have been developed for presenting the effects of methodological, structural, and parameter uncertainty on model results. To help bring these techniques into mainstream use, the authors present a step-by-step guide that offers an integrated approach to account for different kinds of uncertainty in the same model, along with a checklist for assessing the way in which uncertainty has been incorporated. The guide also addresses special situations such as when a source of uncertainty is difficult to parameterize, resources are limited for an ideal exploration of uncertainty, or evidence to inform the model is not available or not reliable. Methods for identifying the sources of uncertainty that influence results most are also described. Besides guiding analysts, the guide and checklist may be useful to decision makers who need to assess how well uncertainty has been accounted for in a decision-analytic model before using the results to make a decision.

Comparative review of three cost-effectiveness models for rotavirus vaccines in national immunization programs; a generic approach applied to various regions in the world

Postma, M. J., Jit, M., Rozenbaum, M. H., Standaert, B., Tu, H. A., & Hutubessy, R. C. (n.d.).

Publication year

2011

Journal title

BMC Medicine

Volume

9

10.1186/1741-7015-9-84

Abstract

Abstract

Background: This study aims to critically review available cost-effectiveness models for rotavirus vaccination, compare their designs using a standardized approach and compare similarities and differences in cost-effectiveness outcomes using a uniform set of input parameters.Methods: We identified various models used to estimate the cost-effectiveness of rotavirus vaccination. From these, results using a standardized dataset for four regions in the world could be obtained for three specific applications.Results: Despite differences in the approaches and individual constituting elements including costs, QALYs Quality Adjusted Life Years and deaths, cost-effectiveness results of the models were quite similar. Differences between the models on the individual components of cost-effectiveness could be related to some specific features of the respective models. Sensitivity analysis revealed that cost-effectiveness of rotavirus vaccination is highly sensitive to vaccine prices, rotavirus-associated mortality and discount rates, in particular that for QALYs.Conclusions: The comparative approach followed here is helpful in understanding the various models selected and will thus benefit (low-income) countries in designing their own cost-effectiveness analyses using new or adapted existing models. Potential users of the models in low and middle income countries need to consider results from existing studies and reviews. There will be a need for contextualization including the use of country specific data inputs. However, given that the underlying biological and epidemiological mechanisms do not change between countries, users are likely to be able to adapt existing model designs rather than developing completely new approaches. Also, the communication established between the individual researchers involved in the three models is helpful in the further development of these individual models. Therefore, we recommend that this kind of comparative study be extended to other areas of vaccination and even other infectious disease interventions.

Comparing bivalent and quadrivalent human papillomavirus vaccines : Economic evaluation based on transmission model

Jit, M., Chapman, R., Hughes, O., & Choi, Y. H. (n.d.).

Publication year

2011

Journal title

BMJ (Online)

Volume

343

Issue

7825

10.1136/bmj.d5775

Abstract

Abstract

Objectives: To compare the effect and cost effectiveness of bivalent and quadrivalent human papillomavirus (HPV) vaccination, taking into account differences in licensure indications, protection against non-vaccine type disease, protection against disease related to HPV types 6 and 11, and reported long term immunogenicity. Design: A model of HPV transmission and disease previously used to inform UK vaccination policy, updated with recent evidence and expanded to include scenarios where the two vaccines differ in duration of protection, cross protection, and end points prevented. Setting: United Kingdom. Population: Males and females aged 12-75 years. Main outcome measure: Incremental cost effectiveness ratios for both vaccines and additional cost per dose for the quadrivalent vaccine to be equally cost effective as the bivalent vaccine. Results: The bivalent vaccine needs to be cheaper than the quadrivalent vaccine to be equally cost effective, mainly because of its lack of protection against anogenital warts. The price difference per dose ranges from a median of £19 (interquartile range £12-£27) to £35 (£27-£44) across scenarios about vaccine duration, cross protection, and end points prevented (assuming one quality adjusted life year (QALY) is valued at £30 000 and both vaccines can prevent all types of HPV related cancers). Conclusions: The quadrivalent vaccine may have an advantage over the bivalent vaccine in reducing healthcare costs and QALYs lost. The bivalent vaccine may have an advantage in preventing death due to cancer. However, considerable uncertainty remains about the differential benefit of the two vaccines.

Cost-effectiveness of universal rotavirus vaccination in reducing rotavirus gastroenteritis in Ireland

Jit, M., Tilson, L., Jit, M., Schmitz, S., Walsh, C., Garvey, P., McKeown, P., & Barry, M. (n.d.).

Publication year

2011

Journal title

Vaccine

Volume

29

Issue

43

Page(s)

7463-7473

10.1016/j.vaccine.2011.07.056

Abstract

Abstract

We evaluated the cost-effectiveness of universal infant rotavirus (RV) vaccination compared to current standard of care of "no vaccination". Two RV vaccines are currently licensed in Ireland: Rotarix™ and RotaTeq™. A cohort model used in several European countries was adapted using Irish epidemiological, resource utilisation and cost data. The base case model considers the impact of Rotarix vaccination on health-related quality of life of children under five years old from a healthcare payer perspective. Other scenarios explored the use of RotaTeq, impact on one caregiver, on societal costs and on cases that do not seek medical attention. Cost was varied between the vaccine list price (€100/course) in the base case and an assumed tender price (€70/course). One-way and probabilistic sensitivity analyses were conducted. Implementing universal RV vaccination may prevent around 1970 GP visits, 3280 A&E attendances and 2490 hospitalisations. A vaccination programme was estimated to cost approximately €6.54 million per year but €4.65 million of this would be offset by reducing healthcare resource use. The baseline ICER was €112,048/QALY and €72,736/QALY from the healthcare payer and societal perspective, respectively, falling to €68,896 and €43,916/QALY, respectively, if the impact on one caregiver was considered. If the price fell to €70 per course, universal RV vaccination would be cost saving under all scenarios. Results were sensitive to vaccination costs, incidence of RV infection and direct medical costs. Universal RV vaccination would not be cost-effective under base case assumptions. However, it could be cost-effective at a lower vaccine price or from a wider societal perspective.

Dedicated outreach service for hard to reach patients with tuberculosis in London : Observational study and economic evaluation

Jit, M., Stagg, H. R., Aldridge, R. W., White, P. J., & Abubakar, I. (n.d.).

Publication year

2011

Journal title

BMJ (Online)

Volume

343

Issue

7826

10.1136/bmj.d5376

Abstract

Abstract

Objective: To assess the cost effectiveness of the Find and Treat service for diagnosing and managing hard to reach individuals with active tuberculosis. Design: Economic evaluation using a discrete, multiple age cohort, compartmental model of treated and untreated cases of active tuberculosis. Setting: London, United Kingdom. Population: Hard to reach individuals with active pulmonary tuberculosis screened or managed by the Find and Treat service (48 mobile screening unit cases, 188 cases referred for case management support, and 180 cases referred for loss to follow-up), and 252 passively presenting controls from London's enhanced tuberculosis surveillance system. Main outcome measures Incremental costs, quality adjusted life years (QALYs), and cost effectiveness ratios for the Find and Treat service. Results The model estimated that, on average, the Find and Treat service identifies 16 and manages 123 active cases of tuberculosis each year in hard to reach groups in London. The service has a net cost of £1.4 million/year and, under conservative assumptions, gains 220 QALYs. The incremental cost effectiveness ratio was £6400-£10 000/QALY gained (about €7300-€11 000 or $10 000-$16 000 in September 2011). The two Find and Treat components were also cost effective, even in unfavourable scenarios (mobile screening unit (for undiagnosed cases), £18 000-£26 000/QALY gained; case management support team, £4100-£6800/QALY gained).

Human papillomavirus vaccine introduction in low-income and middle-income countries : Guidance on the use of cost-effectiveness models

Jit, M., Demarteau, N., Elbasha, E., Ginsberg, G., Kim, J., Praditsitthikorn, N., Sinanovic, E., & Hutubessy, R. (n.d.).

Publication year

2011

Journal title

BMC Medicine

Volume

9

10.1186/1741-7015-9-54

Abstract

Abstract

Background: The World Health Organization (WHO) recommends that the cost effectiveness of introducing human papillomavirus (HPV) vaccination is considered before such a strategy is implemented. However, developing countries often lack the technical capacity to perform and interpret results of economic appraisals of vaccines. To provide information about the feasibility of using such models in a developing country setting, we evaluated models of HPV vaccination in terms of their capacity, requirements, limitations and comparability.Methods: A literature review identified six HPV vaccination models suitable for low-income and middle-income country use and representative of the literature in terms of provenance and model structure. Each model was adapted by its developers using standardised data sets representative of two hypothetical developing countries (a low-income country with no screening and a middle-income country with limited screening). Model predictions before and after vaccination of adolescent girls were compared in terms of HPV prevalence and cervical cancer incidence, as was the incremental cost-effectiveness ratio of vaccination under different scenarios.Results: None of the models perfectly reproduced the standardised data set provided to the model developers. However, they agreed that large decreases in type 16/18 HPV prevalence and cervical cancer incidence are likely to occur following vaccination. Apart from the Thai model (in which vaccine and non-vaccine HPV types were combined), vaccine-type HPV prevalence dropped by 75% to 100%, and vaccine-type cervical cancer incidence dropped by 80% to 100% across the models (averaging over age groups). The most influential factors affecting cost effectiveness were the discount rate, duration of vaccine protection, vaccine price and HPV prevalence. Demographic change, access to treatment and data resolution were found to be key issues to consider for models in developing countries.Conclusions: The results indicated the usefulness of considering results from several models and sets of modelling assumptions in decision making. Modelling groups were prepared to share their models and expertise to work with stakeholders in developing countries.Please see related article: http://www.biomedcentral.com/1741-7007/9/55.

Modelling borderline and mild dysplasia associated with HPV 6 and 11 infection

Chapman, R., Soldan, K., & Jit, M. (n.d.).

Publication year

2011

Journal title

Vaccine

Volume

29

Issue

16

Page(s)

2881-2886

10.1016/j.vaccine.2011.02.008

Abstract

Abstract

Introduction: Low risk HPV types 6/11 are responsible for some low-grade cytological abnormalities. Most economic analyses of HPV vaccination have estimated the additional benefit of HPV 6/11 protection by the quadrivalent vaccine, over the bivalent, based on reduction of genital warts but have not included reduction in repeat smears and colposcopies due to low-grade abnormalities. We investigate the contribution of HPV types 6/11 to abnormal smears and associated costs in England. Methods: The risk of borderline or mild dysplasia due to HPV 6/11 infection was estimated from a study of type-specific HPV DNA in cervical screening specimens collected throughout England. A Markov model representing 10 million women with HPV 6/11 or with no HPV infection from 24 to 64 years was developed to estimate the number of abnormal smears, subsequent repeat smears and colposcopies due to HPV 6/11 associated with borderline or mild dysplasia. Fitting was achieved by varying the force of infection, probability of borderline or mild dysplasia if HPV-uninfected or infected with HPV 6/11 and the duration of infection. Results: The relative risks of borderline or mild dysplasia when infected with HPV 6/11 compared to not being HPV infected were 6.32 (95% credible interval 1.56-25.6) and 17.5 (1.02-300) respectively. Using best fitting parameters we find the costs incurred are between £170 and £195 per abnormal smear due to infection with HPV 6/11. Conclusions: In England, the impact of cytological abnormalities due to HPV 6/11 is relatively small, but not negligible. A vaccine that protects against HPV 6/11 infections could reduce costs associated with borderline and mild dysplasia, and associated colposcopies. These benefits should be considered when formulating immunisation policy, if possible. Smears and colposcopies in those uninfected with HPV far outnumber those in women infected with HPV 6/11.

Modelling the epidemiology of infectious diseases for decision analysis : A primer

Jit, M., & Brisson, M. (n.d.).

Publication year

2011

Journal title

PharmacoEconomics

Volume

29

Issue

5

Page(s)

371-386

10.2165/11539960-000000000-00000

Abstract

Abstract

The number of economic evaluations related to infectious disease topics has increased over the last 2 decades. However, many such evaluations rely on models that do not take into account unique features of infectious diseases that can affect the estimated value of interventions against them. These include their transmissibility from infected to susceptible individuals, the possibility of acquiring natural immunity following recovery from infection and the uncertainties that arise as a result of their complex natural history and epidemiology. Modellers conducting economic evaluations of infectious disease interventions need to know the main features of different types of infectious disease models, the situations in which they should be applied and the effects of model choices on the cost effectiveness of interventions.