Rarer Variant Of Mpox Confirmed In LA County, 1st In US Not Linked To Travel

Health officials in Los Angeles County have confirmed two cases of clade I mpox, a different strain of the disease that typically causes more severe illness.

The cases are the first known ones in the U.S. involving patents without any history of international travel to areas where the virus is usually found, according to health officials.

Only about eight cases of clade I mpox have been confirmed nationally, health officials said.

The first case was announced by the Long Beach Department of Health and Human Services on Tuesday. The patient, a Long Beach resident, was hospitalized and is now isolating and recovering at home, according to health officials.

Another case was announced Thursday by the Los Angeles County Department of Public Health. The patient was also hospitalized and is recovering at home, officials said. That person's city of residence was not revealed.

Clade I mpox is a more serious strain of mpox than clade II, which led to a 2022-23 mpox outbreak in the U.S. Clade I generally causes more severe illness.

Clade I mpox has a reported mortality rate of between 1 and 10%, according to Johns Hopkins.

Clade I mpox has been primarily found in Central and Eastern Africa.

"While the overall risk of mpox clade I exposure to the public remains low, 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 statement. "This underscores the importance of continued surveillance, early response and vaccination."

The more common clade II variant is mostly transmitted through same-sex sexual contact, while clade I is "mostly transmitted through exposure to animals who carry the disease, household contacts, close sexual or intimate contact, and contaminated objects," according to Johns Hopkins.

The disease has been spread through both heterosexual and same-sex sexual contact in Central Africa, according to the university.

Symptoms include a rash or sores that look like pimples or blisters on the face, body and genitals, as well as fever, chills, headache, muscle aches or swollen lymph nodes.

"The identification of cases of clade I mpox, which may cause more severe illness than the more common clade II, is concerning," Dr. Muntu Davis, Los Angeles County health officer, said in a statement. "Mpox continues to be spread largely through close, intimate contact with symptomatic people, mainly during sexual activity. Early detection, testing and vaccination are vital to controlling the spread of this virus. Getting both doses of the JYNNEOS vaccine provides the best protection against mpox."

The JYNNEOS two-dose vaccine is available for everyone, but Los Angeles County health authorities have previously urged those at higher risk of contracting the virus to get the shots. That includes:

• Men or transgender people who have sex with men or transgender people
• People of any gender or sexual orientation who have sex or intimate physical contact with others at large public events or engage in commercial or transactional sex
• People living with HIV, especially those with uncontrolled or advanced HIV disease
• Sexual partners or people in any of the above groups

City News Service contributed to this report.