As the number of monkeypox cases in the UK rose to 71 on Tuesday, a report has revealed that people afflicted by the viral disease may actually be infectious long after their scabs and rashes have healed.
A study published by the Lancet Infectious Diseases journal has poured cold water on the theory that monkeypox patients are no longer contagious once their lesions have disappeared.
The Lancet report looked at seven people who had monkeypox – a close relative of the smallpox virus – in Britain between 2018 and 2021, with all cases linked to Africa.
None of the patients died or needed intensive care treatment, but some were admitted to hospital as a precaution to prevent any onward transmission.
Co-author Dr Hugh Adler, a research fellow at the Liverpool School of Tropical Medicine, said: “We can see the virus remains positive in the throat and blood for the length of the illness and maybe even longer after the rash is resolved.
“We don’t know that this means these patients are more infectious or infectious for longer, but it does inform us of the biology of disease.”
Fellow co-author Dr Catherine Houlihan, of the UK Health Security Agency and University College London, added: “During previous outbreaks of monkeypox, patients were considered infectious until all lesions crusted over.
“In these seven UK cases, viral shedding was observed for at least three weeks following infection.
“However, data on infectivity remains limited, and is an important area for future study.”
Experts have also allayed parents’ fears about children catching the disease.
Dr David Porter, a paediatric infectious diseases consultant at Alder Hey Children’s NHS Foundation Trust, admitted that cases in the UK were rare.
He said: “As a parent with a child that might develop a rash, I don’t think parents should be worried about this being monkeypox at this stage, because we’re seeing a very low number of cases.
“And in all the previous outbreaks that have occurred outside of Africa over the last few years, we’ve seen very rare numbers of cases in children, so it’s been predominantly in adults.”
The study also suggests that some antiviral medications might have the potential to shorten symptoms and reduce the amount of time a patient is contagious.
The cases analysed represent the first instances of in-hospital transmission and household transmission outside of Africa, as well as reporting the patient response to the first off-label use of two different antiviral medications – brincidofovir and tecovirimat (drugs designed to target smallpox) – to treat the disease.
The report found little evidence that brincidofovir was of clinical benefit, but did conclude that further research into the potential of tecovirimat would be warranted.
The study did not look at the current outbreak in Britain, with the majority of the 71 cases catching it in the community, and a sizeable proportion in gay and bisexual men.
Dr Nick Price, of Guy’s & St Thomas’ NHS Foundation Trust, a senior author on the paper, added: “Until now, monkeypox has been a rare, imported condition in the UK and the NHS High Consequence Infectious Diseases Network has treated all seven of the UK’s confirmed cases until 2021.
“Outbreaks outside of Africa are unusual but in recent days, significant outbreaks have been reported in several European countries, including the UK, and further afield globally.
“Clinical trial data is lacking and we are pleased to share some of our collective experience in managing this previously rare and sporadic condition.”
