California officials confirm 1st US case of severe mpox strain with no travel history

(NEW YORK) — The first U.S. case of a more severe strain of mpox without any recent travel history has been identified in California.

Health officials said this week that the case was confirmed in a Long Beach resident. The patient required hospitalization and is now isolating and recovering at home.

No other identifying details were provided about the patient, including name, age or sex.

While this is the seventh case of the more severe strain confirmed in the U.S this year, it is the first without known travel, according to local officials.

Officials say the risk to the general public is low and the health department is conducting an investigation, including working to identify the patient’s potential sources of exposure.

“We are taking this very seriously and ensuring our community and health care partners remain vigilant so we can prevent any more cases,” Long Beach Mayor Rex Richardson said in a press release. “This underscores the importance of continued surveillance, early response and vaccination.”

There are two types of the virus that cause mpox: clade I and clade II, with clade roughly meaning they are descended from a common ancestor organism. Clade I has historically been associated with severe illness and death, and is endemic to parts of central and western Africa, according to the Centers for Disease Control and Prevention (CDC).

Clade II was responsible for a large outbreak that peaked in summer 2022, leading to more than 100,000 cases in 122 countries, including more than 30,000 cases in the U.S.

The less severe strain in the U.S. has continued circulating at low levels and has remained relatively stable.

Parts of Africa have been dealing with sustained person-to-person spread of the more severe strain of mpox. All six previously confirmed cases of the more severe strain in the U.S. have been among people who had recently traveled to areas associated with the outbreak in central and eastern Africa, according to the CDC.

In November 2024, California reported the first domestic case of the more severe strain in a traveler from Africa who experienced mild illness.

People with mpox, which was formerly known as monkeypox, often get a rash that can be located on hands, feet, chest, face, mouth or near the genitals, the CDC said.

Most people with mpox typically recover within two to four weeks without specific treatments.

Currently, the JYNNEOS vaccine, a two-dose vaccine approved by the Food and Drug Administration to prevent smallpox and mpox, is the only vaccine being used in the U.S.

The JYNNEOS vaccine is  recommended for adults at high risk for mpox, which includes people who are gay, bisexual or other men who have sex with men and have recent or upcoming risk factors like multiple sexual partners, intimate contact with someone who may have mpox, or sex at commercial venues.

ABC News’ Mary Kekatos contributed to this report.

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