The monkeypox outbreak in the UK is not yet under control, experts have warned, with some suggesting that vaccines may need to be offered to all men who have sex with men.
Monkeypox, which is to be given a new name by the World Health Organization (WHO), is typically found in west and central Africa, but an unprecedented outbreak in recent weeks has resulted in cases appearing in a host of countries from France to Canada and Australia. It is understood the WHO will hold a meeting next week to decide whether to label the outbreak as a public health emergency of international concern.
As of 12 June, 470 cases had been identified in the UK, including a rise of 104 cases reported in England last Monday. Experts are warning further action may be needed to curb the rise.
“At the moment there is no clear evidence that the current epidemic is coming under control,” said Paul Hunter, a professor of medicine at the University of East Anglia.
Cases so far have predominately been found among men who are gay or bisexual or otherwise have sex with men – although experts have raised concerns around particular communities becoming stigmatised, stressing anyone can get monkeypox and that it is spread between humans through close contact.
A smallpox vaccine that also offers protection against monkeypox is available, with current guidelines advising jabs should ideally be given to close contacts of cases within four days of exposure to monkeypox to prevent or lessen the impact of infection, although in some circumstances it can be given to individuals up to 14 days after exposure to reduce symptoms should infection have occurred.
“I guess that if we do not see this coming under control very soon, then we are looking at offering vaccination to all men who have sex with men, and possibly female sex workers,” said Hunter.
Prof Jimmy Whitworth of the London School of Hygiene and Tropical Medicine also raised concerns. “These numbers of new cases suggest that we are not yet getting the monkeypox epidemic under control,” he said, although he cautioned it was necessary to look at the trend in cases over a longer period, while it could take a week or two before the number of new cases fell once transmission was under control.
But Whitworth said it was clearly a very challenging outbreak to control. “There seem to have been some superspreading events that have enabled infections to spread rapidly into many different countries, and there are chains of transmission that suggest that there might have been some cases without any obvious signs of infection which has allowed further spread which has not been detected,” he said.
Hunter said there were probably many factors at play. “The thing that worries me the most is that for a disease whose transmission may have significant stigma for some is that people may not be fully honest about their contacts and if that is the case then a public education and a ring vaccination strategy approach may not be sufficient,” he said, adding another concern was how well contacts were adhering to the self-isolation period.
“For someone who is not openly gay having to self-isolate for 21 days would be tantamount to coming out,” Hunter said, noting the situation was sensitive and complex, particularly for bisexual men who have not come out to their female partners.
According to the UK Health Security Agency (UKHSA), individuals who have been tested are usually informed of their result within 24 hours, with contacts identified and followed up with as soon as possible, and vaccination offered if appropriate.
However, the agency has flagged challenges with the outbreak, noting: “Most cases reported having sexual contact with new or casual partners, sometimes in the context of cruising grounds or during chemsex, frequently where contact details were unavailable for tracing.”
Dr Michael Head, a senior research fellow in global health at the University of Southampton, said public health teams in the UK and internationally had done an excellent job, both with contact tracing and reporting as well as accurate and sensitive public health messaging.
Head said there was a small signal in UK data that the outbreak was slowing down – although this was not yet certain – while the lack of infections within the wider community showed transmission relied on very close contact.
“This is less complex to address than, for example, a Covid-19 outbreak, and gives encouragement that the outbreak will be brought to an end in the coming weeks or months,” he said.
Dr Hugh Adler of the Liverpool School of Tropical Medicine said there could be a positive view of the rising case numbers. “Maybe this is [reflecting] that the public health messaging is getting out and people are presenting for assessment,” he said.
Adler said vaccination was not appropriate for all contacts of cases, particularly if they did not have close or intimate contact. Instead such individuals can be monitored for possible symptoms.
“Their risk is so low that vaccination wouldn’t be the right thing for them anyway, because of our limited supplies of the vaccine, as well as side-effects,” he said.
