Three Pressing Questions About Monkeypox: Spread, Vaccination, Treatment

Monkeypox, once a relatively obscure virus endemic to Africa, has bloomed into a global threat, infecting more than 20,000 people in 75 countries and forcing the World Health Organization to declare a worldwide health emergency.

On Thursday, New York State and San Francisco declared emergencies of their own. But even as the national tally nears 5,000 cases and experts warn that containment is slipping away, federal health officials have not followed suit.

One reason: This virus — unlike the coronavirus — is a known enemy, officials say. Doctors understand how it spreads, and there already are tests, vaccines and treatments.