County Public Health Confirms Its First Case of Clade I Mpox

The Los Angeles County Department of Public Health has confirmed its first case of clade I mpox in an adult with no recent travel to regions where this virus is typically found. The individual was hospitalized and is now recovering at home.

This is the second clade I mpox case in LA County and the second in the nation without known travel to another country where clade I is typically found. The City of Long Beach, which has its own health department, also announced a separate clade I mpox case earlier this week.

Public Health is collaborating with California Department of Public Health and the U.S. Centers for Disease Control and Prevention to investigate these mpox cases as swiftly and effectively as possible. Enhanced surveillance and contact tracing are underway to identify any additional cases and potential sources of the infection and to prevent further transmission.

How Mpox Clade I and Clade II Differ

Mpox is caused by two main types or clades of the mpox virus: clade I and clade II.

Clade II causes mild to moderate illness and has been circulating at low levels in the United States since 2022.

Clade I may be more severe than clade II and has recently been linked to outbreaks in some African countries since 2024. Clade I mpox may spread more easily than clade II mpox, including through close personal contact (like massage or cuddling) in addition to sex.

Both clade I and clade II may present with flu-like symptoms followed by a rash, and can be spread through close personal contact and within households or by sharing personal items. Laboratory testing of lesions can confirm a diagnosis for clade I and clade II mpox.

So far in 2025, Public Health has reported 118 cases of clade II mpox.

Public Health strongly recommends:Get Vaccinated. Vaccination with both doses remains an effective tool in preventing the spread of mpox. The JYNNEOS vaccine is a safe, two-dose vaccine that helps protect against both clade I and clade II mpox, and getting both doses provides the best protection.

For the most up-to-date information and resources, please visit ph.lacounty.gov/mpox or contact the Public Health info line at 1-833-540-0473, seven days a week, 8a.m. to 8 p.m.