The study, co-led by the University of Bristol, the UK Health Security Agency (UKHSA), and the National Institute for Health and Care Research (NIHR), evaluated the most cost-effective way to minimise future mpox outbreaks among gay and bisexual men through vaccination.
It found that all vaccination strategies significantly reduced the likelihood of outbreaks and their associated costs while also resulting in improved health-related quality of life among affected groups, compared to no vaccination.
Continuous vaccination, with increased vaccination during outbreaks, was shown to be the most successful strategy offering savings of some £9million and reducing the number of projected cases from 11,000 to 1,000 over ten years.
Joint senior author Peter Vickerman, Professor of Infectious Disease Modelling at the University of Bristol, said: “Our findings highlight the critical role of vaccination in limiting the spread of mpox. Moreover, the study results also illustrate how proactive vaccination in a routine programme for groups at risk of mpox provides better health outcomes and also saves health services a lot of money, so it’s a clear win-win.”
Mpox, previously known as monkeypox, is a viral illness which is most prevalent in parts of central and east Africa.
The researchers, from the National Institute for Health and Care Research (NIHR) Health Protection Research Unit (HPRU) in Evaluation and Behavioural Science based at the University of Bristol, developed their model using health data from England in 2022, when a global mpox outbreak occurred, mainly affecting gay and bisexual men. In England this outbreak was dramatically reduced through health promotion, changes in sexual behaviour, and vaccinating gay and bisexual men at highest risk of infection.
Costs were estimated for case management, vaccination, and public health responses during this outbreak. The researchers used their model to look at what vaccination strategies are needed to prevent future outbreaks, with costs arising from the 2022 outbreak being used to estimate costs of any future outbreaks and continuing vaccination.
Although mpox is rare, there is an expanding outbreak of a strain of mpox called Clade Ib in Sub-Saharan Africa, spread within households, and through close contact including sexual contact.
While the research model focused on transmission within sexual networks of gay and bisexual men, the research team hope to expand the study to consider the impact of, and best way to prevent sustained transmission, in the whole population in England. This would include scenarios where mpox was transmitted through sex between men and women.
Prof Vickerman explained: “Our analyses show that all modelled vaccination strategies are likely to be cost-saving, decrease the number of infections and improve quality of life compared to not vaccinating. Continuous vaccination at a low rate, potentially with increased vaccination during outbreaks, was found to be the most cost-effective strategy. This finding is robust over most sensitivity analyses with mpox vaccination remaining cost-effective below a vaccine price threshold.”
Dr Sema Mandal, Consultant Epidemiologist and Deputy Director of Public Health Programmes at UKHSA, added: “As this study shows, vaccination plays an essential role in helping to reduce mpox cases and preventing future outbreaks.
“With mpox vaccination now available in every region of England for those at increased risk of infection, getting vaccinated is easier than ever before. If you are eligible, please do make sure you have had the vaccine to protect yourself from mpox.”
The study was funded by the University of Bristol and UKHSA’s NIHR HPRU in Evaluation and Behavioural Sciences in partnership with University College London and UKHSA’s NIHR HPRU in Blood Borne and Sexually Transmitted Infections.
Paper
‘Cost-effectiveness of vaccination strategies to control future mpox outbreaks in England: a modelling study’ by Xu-Sheng Zhang et al in The Lancet Regional Health - Europe