NEW YORK (AP) Reacting to a surprising and growing monkeypox outbreak, U.S. health officials on Tuesday expanded the group of people recommended to get vaccinated against the monkeypox virus.

They also said they are providing more monkeypox vaccine, working to expand testing, and taking other steps to try to get ahead of the outbreak.

We will continue to take aggressive action against this virus, said Dr. Ashish Jha, White House COVID-19 response coordinator, who has also been playing a role in how the government deals with monkeypox.

The administration said it was expanding the pool of people who are advised to get vaccinated to include those who may realize on their own that they could have been infected. That includes men who who have recently had sex with men at parties or in other gatherings in cities where monkeypox cases have been identified.

Most monkeypox patients experience only fever, body aches, chills and fatigue. People with more serious illness may develop a rash and lesions on the face and hands that can spread to other parts of the body.

The disease is endemic in parts of Africa, where people have been infected through bites from rodents or small animals. It does not usually spread easily among people.

Last month, cases began emerging in Europe and the United States. Many but not all of those who contracted the virus had traveled internationally. Most were men who have sex with men, but health officials stress that anyone can get monkeypox.