States will be given vaccine doses from the federal stockpile, but supplies of the safest type are limited.

Clinics nationwide will begin offering vaccinations against monkeypox to anyone who may have been exposed to the virus, federal health officials announced on Tuesday.

States will receive doses of a safer and newer monkeypox vaccine called Jynneos from the federal stockpile, based on the number of cases and the proportion of the state’s population at risk for severe disease, the officials said at a news briefing.

State health authorities may also request supplies of an older vaccine developed for smallpox, which is believed to protect against monkeypox, as well.

The Department of Health and Human services will provide 56,000 doses of the Jynneos vaccine immediately and an additional 240,000 doses in the coming weeks.

Some experts said the plan was also unfair to men at risk who will not have access to the Jynneos vaccine, especially those who have H.I.V.

The Jynneos vaccine, on the other hand, has never been used on this scale, and federal health officials said they would watch for unexpected side effects.

The administration has so far provided more than 9,000 doses of Jynneos vaccine and 300 courses of antiviral treatments to 32 jurisdictions in the country, officials said on Tuesday.

Washington’s health department offered 300 monkeypox vaccination appointments on Monday; the slots filled up in less than 15 minutes.

New York City, which had identified 55 cases of monkeypox as of Tuesday, had 1,000 doses of the Jynneos vaccine at hand.