Last year, UKHSA was the first in the world to identify an outbreak of mpox in 2022, immediately influencing global health partners to control further transmission and ensure vaccines are available to those most at risk in the UK.
A year later, the number of cases has dropped dramatically, with just 10 new cases since the start of 2023. Vaccination has played a crucial role in protecting people from mpox and reducing the number of cases. People who are eligible but have not yet received 2 doses of the vaccine are encouraged to come in and book their first dose by June 16, 2023, and get their second dose by the end of July 2023.
The 2022 outbreak was the first time that such Mpox outbreaks were observed simultaneously in multiple non-endemic countries. For clinicians and scientists around the world, this new outbreak presents many unknowns and underscores the need for rapid research so they can better understand how the virus is transmitted, who is affected, and what interventions can be used to protect those at highest risk.
One year after the first case of this outbreak was identified, we reflect on some of the key lessons we’ve learned that have shaped our response and will influence how we limit or prevent future outbreaks.
1) Certain groups have been disproportionately affected
Clinicians and scientists worked quickly at the start of the outbreak to better understand the community transmission that was occurring in the UK. Early analysis of cases and their contacts found that most cases were gay, bisexual and other men who have sex with other men, a trend that continued throughout the outbreak.
Understanding who was at highest risk of exposure to mpox is crucial to the public health response in the UK, underpinning everything from communication to vaccine eligibility. A £200,000 fund has been set up to help reduce sexual health inequalities in disadvantaged LGBT+ communities, with the aim of testing new ways to improve sexual health and HIV outcomes.
2) How mpox is transmitted has changed
Until the outbreak of the mpox epidemic in 2022, transmission was generally thought to occur between animals and humans (zoonotic transmission) through close contact with animals that have mpox. A significant amount of research has been undertaken in the last year to understand transmission in this outbreak, with regular publication of data by the UKHSA and WHO, summarized in the UKHSA Transmission Review. Evidence consistently suggests that transmission of mpox in this outbreak occurred primarily through intimate sexual contact, representing a significant change in the epidemiology of mpox with significant implications for our response and future surveillance.
3) Mpox can be transmitted before symptoms are detected
UKHSA modelling, based on a review of surveillance and contact tracing data in the UK between 6 May and 1 August 2022, found evidence of transmission of mpox before symptoms were identified (subclinical transmission). The researchers estimated that more than half (53%) of transmissions occurred four days before symptoms developed or were detected, with an average incubation period of 7-8 days. This was the first study ever to demonstrate presymptomatic transmission of the smallpox virus.
4) Although mpox infection is mild for most people, it can also cause severe symptoms
For those who are immunocompromised, mpox infection may be associated with more severe symptoms. An international collaboration of doctors led by Queen Mary University of London and Barcelona’s Fight Infectious Foundation/Hospital Germans Trias has identified a severe form of mpox in immunocompromised people living with advanced HIV. They called for it to be added to the World Health Organization and Centers for Disease Control and Prevention’s list of serious infections considered particularly dangerous for people with advanced HIV disease.
5) Vaccination offers strong protection against mpox
A review of data on monkeypox cases and vaccination uptake between 4 July and 3 November 2022 in England found that a single dose of MVA-BN vaccine 14 days after vaccination provides about 78% protection against mpox. This indicates that vaccination is critical to protect those at highest risk of exposure to mpox and prevent further outbreaks.
The recently launched LIMIT study aims to better understand how the body responds to the mpox virus and produces antibodies by comparing antibody levels in people after an mpox vaccination, mpox infection or both to see what kind of antibody response each causes and how long they last.
6) Public awareness of mpox is the key to prevention
A report on the role of vaccination and public awareness around mpox found that public awareness of monkeypox and subsequent behavior change had a significant impact on the trajectory of mpox in the UK. It also found that the introduction of the vaccine is critical to reducing the risk of mpox resurgence in the UK in the medium term. People who are eligible but have not yet received 2 doses of the vaccine are encouraged to come in and book their first dose by June 16, 2023, and get their second dose by the end of July 2023.
7) There is still much to learn
Thanks to the public following our advice to reduce transmission, and the NHS, public health professionals and third sector organizations stepping up and working hard to reduce the incidence of mpox, the number of new cases reported has fallen significantly. Only 10 new cases have been identified so far in 2023, half (5) of which are believed to have been acquired outside the UK, but research is ongoing to better understand mpox.
Our LIMIT study will help us understand how the body responds to the mpox virus, an area where there hasn’t been much research.
We continue our work with partners to avoid a resurgence of mpox and reach our ultimate goal of eradication. Vaccination is key to reducing the severity of symptoms and preventing further transmission. People who are eligible but have not yet received 2 doses of the vaccine are encouraged to come in and book their first dose by June 16, 2023, and get their second dose by the end of July 2023.
You can find an mpox vaccination website through NHS.UK.