Expert: Monkeypox likely spread by sex at two raves in Europe

LONDON — A leading adviser to the World Health Organization described the unprecedented outbreak of monkeypox in developed countries as “a random event” that might be explained by sexual behavior at two recent raves in Europe.

Dr. David Heymann, who formerly headed WHO’s emergencies department, told The Associated Press that the leading theory to explain the spread of the disease was sexual transmission at raves held in Spain and Belgium. Monkeypox has not previously triggered widespread outbreaks beyond Africa, where it is endemic in animals.

“We know monkeypox can spread when there is close contact with the lesions of someone who is infected, and it looks like sexual contact has now amplified that transmission,” said Heymann.

That marks a significant departure from the disease’s typical pattern of spread in central and western Africa, where people are mainly infected by animals like wild rodents and primates and outbreaks have not spilled across borders.

Health officials say most of the known cases in Europe have been among men who have sex with men, but anyone can be infected through close contact with a sick person, their clothing or bedsheets. Scientists say it will be difficult to disentangle whether the spread is being driven by sex or merely close contact.

“By nature, sexual activity involves intimate contact, which one would expect to increase the likelihood of transmission, whatever a person’s sexual orientation and irrespective of the mode of transmission,” said Mike Skinner, a virologist at Imperial College London.

On Monday, the European Centre for Disease Prevention and Control Director Andrea Ammon said “the likelihood of further spread of the virus through close contact, for example during sexual activities among persons with multiple sexual partners, is considered to be high.”

To date, WHO has recorded more than 90 cases of monkeypox in a dozen countries including Canada, Spain, Israel, France, Switzerland, the U.S. and Australia.

U.S. health officials said Monday they knew of one confirmed case, in the state of Massachusetts, and four probable cases — two in Utah, one in Florida and one in New York City. All were men who had traveled outside the U.S.