The government has launched a study, which aims to recruit 2,000 participants in England, to determine whether mpox can be transmitted asymptomatically.
In a statement published on 22 August 2023, the UK Health Security Agency (UKHSA) said the £1m PResymptomatIc MonkEypox (PRIME) study, funded by the Medical Research Council, will inform the public health outbreak response, providing data to support future vaccination and testing strategies.
In July 2022, the World Health Organization declared an outbreak of mpox in non-endemic countries, including those in Europe, North America and Australasia, to be a public health emergency.
An mpox vaccination programme was introduced in the UK in June 2022 in response to the outbreak, following which antiviral treatment became available on the NHS for patients with severe or complicated mpox. The targeted vaccination programme was wound down in June 2023 as the number of cases fell.
However, the government said in its statement that “research has shown that some people can be infected with mpox without showing any symptoms … but these have been small studies and the extent to which this happens is unclear”.
The PRIME study, therefore, aims to clarify how often mpox infection leads to unnoticeable or non-visible symptoms, and if it is possible for people to have been infected and not know.
Nathan Burley, public and sexual health services pharmacist at NHS Greater Glasgow and Clyde, told The Pharmaceutical Journal that the study “represents a step forward in understanding why mpox has jumped into populations previously unaffected”.
“Recruiting 2,000 participants is certainly ambitious, especially with the criteria outlined in the study. I hope people realise the benefit in taking part and the results from this guide a sensible national strategy going forward.”
Anyone in England aged 18 years or over who knows they have been in close sexual contact with an mpox case is eligible to participate, the government has said.
However, Burley added that “a global approach is required” for the study. “We should simultaneously be investing in foreign aid, research and vaccination where mortality from mpox is significantly higher in Central and West African countries,” he said.
Study participants, who will be recruited until September 2023, will be asked to complete a short questionnaire about their exposure to mpox, their vaccination status, and to do a self-collection blood test to check whether they have developed antibodies to the virus.
The team of researchers will include those based at the UKHSA, University College London, London School for Hygiene and Tropical Medicine and non-profit the Love Tank, which focuses on health and wellbeing among under-served communities.
Colin Brown, deputy director at UKHSA and lead researcher for the study, said: “This is an exciting area of research that should provide us with valuable insights into the spread of mpox.
“It will give us a better understanding of who has developed antibodies from vaccination, exposure to the virus, or both. This will inform vaccination and sexual health testing strategies and improve our understanding of how we can prevent or manage future outbreaks and better support those affected.”