Last week, for the second time in two years, the World Health Organization (WHO) declared a “public health emergency of international concern” for mpox. A new version of the virus formerly known as monkeypox is spreading mainly via heterosexual transmission, and turning up in places as far-flung as Kenya and Sweden. There will be more. You may be thinking: didn’t that go away two years ago? Is this one more deadly? Is it easy to catch?
There has been some confusion in what you may have read, and it isn’t surprising. Mpox has morphed into four different diseases in the past few years, and official sources often mash them up. There’s the original clade I in central Africa and clade II in west Africa, which we have known about since the 1970s. Then there is a recently evolved, sexually transmitted “b” version of each. Clade Ib is currently causing the most alarm. And it could be about to cause a pandemic.
