New UKHSA evidence indicates that a single MVA-BN vaccine dose provides around 78% protection against monkeypox 14 days after being vaccinated.
This is the strongest UK evidence yet for the effectiveness of the vaccine. As part of the analysis, monkeypox cases in England and vaccination uptake data between 4 July to 3 November 2022 were reviewed to estimate vaccine effectiveness within the eligible gay, bisexual and men who have sex with men (GBMSM) cohort, with vaccine coverage among cases compared to the wider eligible population.
Out of 363 monkeypox cases in this period, 8 had been vaccinated at least 14 days before and 32 had been vaccinated between 0 to 13 days before. The rest (323) were not vaccinated during this outbreak. This gives an estimate of vaccine effectiveness for a single dose of 78% 14 or more days after vaccination.
The UK Health Security Agency (UKHSA) will continue to investigate the duration of protection from a single dose and the combined protection of 2 doses.
Jamie Lopez-Bernal, Consultant Epidemiologist at UKHSA, said: "While monkeypox cases are low it remains vital to stay alert to the risks. Thank you to everybody who has come forward for their vaccine already – it is helping to keep numbers low, but we can’t get complacent.
"We now know that a single vaccine dose provides strong protection against monkeypox, which shows just how important vaccination is to protect yourself and others. A second dose is expected to offer even greater and longer lasting protection."
NHS National Director of Vaccinations and Screening Steve Russell said: "Thanks to hard-working staff, more than 55,000 doses of the monkeypox vaccine have been delivered so far, and we now know just how effective the vaccine is, offering 78% protection against the virus from just one dose.
"While the risk of monkeypox remains low, we urge anyone eligible to come forward to get their vaccination and with the NHS monkeypox site finder, it’s now easier than ever to book in for a first dose, giving yourself a high level of protection."