(NewsNation) — At least 10 cases of monkeypox have been confirmed in eight states across the country as of Friday morning, according to the Centers for Disease Control and Prevention.

Cases have been identified in California, Florida, Massachusetts, New York, Utah, Virginia, Colorado and Washington.

Earlier this week, President Joe Biden sought to calm concerns about the recent cases, saying he did not see the need to institute strict quarantine measures.

Speaking in Tokyo a day after he said the virus was something “to be concerned about,” Biden said, ”I just don’t think it rises to the level of the kind of concern that existed with COVID-19.”

Health officials this week also said they suspected the disease was spreading through raves and sexual contact. 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.

Monkeypox is primarily spread through the characteristic skin lesions that develop in people who are infected. A person is considered to be infectious until these lesions are fully healed. It is spread mostly through close contact with an infected person, their clothing or their bedsheets.

Although the disease belongs to the same virus family as smallpox, its symptoms are milder. People usually recover within two to four weeks without needing to be hospitalized, but the disease occasionally is deadly.

Monkeypox complications can include secondary infections, bronchopneumonia, sepsis, encephalitis and cornea infections. The virus has been shown in Africa to cause death in as many as 1 in 10 infected people.

This story is developing. Refresh for updates.

The Associated Press and the Hill contributed to this report.