California reports first US mpox case of severe strain without travel history

• Source: www.reuters.com

California, Oct. 16, 2025—Health officials have confirmed the first US mpox case of a severe mpox strain in a person with no recent travel history. The case was identified in a Long Beach resident who required hospitalization and is now isolating and recovering at home, officials said this week.

According to the Long Beach Department of Health and Human Services, this is the seventh confirmed case of the more severe strain of mpox in the United States this year but the first with no known travel link to Africa. Previous cases involved individuals who had traveled to areas where the virus is endemic.

“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.”

Health authorities stated that the risk to the general public remains low. An investigation is ongoing to determine how the patient may have been exposed and to identify any close contacts.

Two clades of the virus of US mpox case

US mpox case , formerly known as monkeypox, is caused by a virus related to smallpox. According to the Centers for Disease Control and Prevention (CDC), there are two major types—clade I and clade II. Clade I has historically been associated with more severe illness and higher fatality rates and is primarily found in central and western Africa.

Clade II caused a global outbreak that peaked in 2022, resulting in more than 100,000 cases in 122 countries, including over 30,000 in the U.S. That outbreak was largely driven by person-to-person transmission, especially through close physical contact.

The less severe clade II strain has continued circulating at low levels in the United States, with most infections leading to mild or moderate symptoms.

Previous US mpox case and ongoing response

Before this recent case, all six U.S. infections involving the more severe clade I strain were detected in travelers returning from Africa, the CDC said. In November 2024, California reported one such case in a traveler who experienced only mild symptoms.

The CDC emphasized that while local transmission of the severe strain has not been confirmed, health officials are monitoring the situation closely. The agency has alerted healthcare providers nationwide to report any suspected mpox cases promptly.

People infected with mpox often develop a rash that can appear on the hands, feet, chest, face, mouth or near the genitals. Symptoms typically resolve within two to four weeks without specific treatment. Severe illness is rare but can occur, especially in individuals with weakened immune systems.

Vaccination and prevention

The JYNNEOS vaccine, approved by the Food and Drug Administration to prevent both smallpox and US mpox case , remains the primary preventive measure. It is given in two doses and recommended for people at higher risk of exposure.

Those at increased risk include gay, bisexual and other men who have sex with men who may have multiple sexual partners, close physical contact with someone infected with mpox, or attend events involving intimate contact.

Officials continue to urge eligible individuals to stay up to date with vaccination, remain aware of symptoms and seek medical advice if they suspect exposure.

While this case marks a concerning development in domestic transmission patterns, both federal and local health authorities reiterated that there is no current evidence of widespread community transmission in the United States.

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