Third case of more severe mpox strain in LA County confirmed, investigation into potential spread underway

The Los Angeles County Department of Public Health is looking into a possible local spread of a more severe strain of the mpox virus after confirming a third local case in a person who has not traveled to a country where the virus is usually found.

"The confirmation of a third case with no travel history raises concerns about possible local spread in Los Angeles County," Dr. Muntu Davis, Los Angeles County Health Officer, said in a statement. "We’re working closely with our partners to identify potential sources and understand how this potentially more serious type of the mpox virus may be spreading."

This week, the department confirmed a case of clade I mpox in an adult who officials say was hospitalized and now recovering at home. Long Beach, which has its own public health department, also confirmed a separate case. All cases were reported in adults without recent travel history and there was no link between them at this time, according to officials.

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These cases of the clade I mpox strain are the first nationally without known travel to places where the virus is usually found. There have been other cases of clade I nationally, and the strain has been linked to outbreaks in some African countries, according to officials.

About the virus

Mpox cases are divided into clade I, a more severe case, and clade II. The cases found in L.A. County are of the more severe strain.

Both types present with flu-like symptoms followed by a rash. Mpox is spread through close person-to-person contact, within households or by sharing personal items.

So far in 2025, there have been 118 cases of the less severe, clade II mpox reported in L.A. County. Last year, the county reported 220 cases, with a sharp uptick in cases reported during the fall.

How to protect yourself

Health officials said vaccinations are the best way to prevent the spread of mpox. The JYNNEOS vaccine is a safe, two-dose vaccine that helps protect against both strains of the virus mpox. Getting both doses provides the best protection.

To locate a nearby pharmacy location with the JYNNEOS vaccine, visit the Bavarian Nordic Vaccine Locator webpage.

You should also get tested if you show symptoms, including rash, fever or swollen lymph nodes.

For more information and resources, visit the L.A. County Public Health's website or contact their hotline at (833) 540-0473. It's available seven days a week, between 8 a.m. and 8 p.m.