Monkeypox has likely spread undetected ‘for some time’: WHO

The World Health Organization (WHO) has said that hundreds of monkeypox cases have surfaced beyond the African countries where the disease is typically found, warning that the virus has likely been spreading under the radar.

“Investigations are ongoing, but the sudden appearance of monkeypox in many countries at the same time suggests there may have been undetected transmission for some time,” WHO Director-General Tedros Adhanom Ghebreyesus told reporters on Wednesday.

Since the United Kingdom first reported a confirmed monkeypox case on May 7, more than 550 confirmed cases of the disease have been verified in 30 countries outside of the west and central African nations where it is endemic, the WHO said.

The United Nations health agency’s top monkeypox expert Rosamund Lewis said that the appearance of so many cases across much of Europe and other countries where it has not been seen before “is clearly a cause for concern, and it does suggest undetected transmission for a while”.

“We don’t know if it is weeks, months or possibly a couple for years,” she said, adding that “we don’t really know if it is too late to contain”.

Monkeypox is related to smallpox, which killed millions around the world every year before it was eradicated in 1980.

But monkeypox, which spreads through close contact, is much less severe, with symptoms typically including a high fever and a blistery chickenpox-like rash that clears up after a few weeks.

Call to fight stigma

So far, most cases have been reported among men who have sex with men, although experts stress there is no evidence that monkeypox is transmitted sexually.

“Anyone can be infected with monkeypox if they have close physical contact with someone else who is infected,” Tedros said.

He urged everyone to help “fight stigma, which is not just wrong, it could also prevent infected individuals from seeking care, making it harder to stop transmission”.

The WHO, he said, was also “urging affected countries to widen their surveillance”.

Lewis insisted it was vital “that we collectively all work together to prevent onward spread,” through contact tracing and isolation of people with the disease.

Vaccines developed for smallpox have also been found to be about 85 percent effective in preventing monkeypox, but they are in short supply.

The WHO is not proposing mass vaccination, but rather targeted use in some settings to protect health workers and people most at risk of infection.

Lewis highlighted that monkeypox cases had also been on the rise in endemic countries, where thousands fall ill from the disease each year, with around 70 deaths from the virus reported across five African countries so far this year.

The fatality rate for monkeypox is usually quite low, and no deaths have been reported among the confirmed cases outside of endemic countries.

But Maria Van Kerkhove, the WHO lead on emerging diseases, warned that while no deaths had been reported, that could change if the virus spreads in more vulnerable populations.

Endemic diseases warning

Meanwhile, the WHO’s emergencies director, Mike Ryan, warned on Wednesday that outbreaks of endemic diseases including monkeypox and lassa fever are becoming more persistent and frequent.

As climate change contributes to rapidly changing weather conditions like drought, animals and human are changing their food-seeking behaviour. As a result, diseases that typically circulate in animals are increasingly jumping into humans, he said.

“Unfortunately,” Ryan warned, “that ability to amplify that disease and move it on within our communities is increasing – so both disease emergence and disease amplification factors have increased.”