Public Health Investigating Possible Local Spread of Clade I Mpox; Third Case Confirmed in Los Angeles County

The Los Angeles County Department of Public Health is investigating the possibility of a local spread of Clade I mpox cases after confirming its second case 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 third clade I mpox case in LA County and the third in the nation without known travel to another country where clade I is typically found. Public Health announced its first case yesterday and, earlier this week, the City of Long Beach, which has its own health department, announced its first case. At this time, no clear link has been identified between the cases.

Public Health continues collaborating closely with California Department of Public Health and the U.S. Centers for Disease Control and Prevention or CDC 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. The CDC is conducting additional testing to identify the virus’s genes (genomic sequencing) in each case.

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.

Both clade I and clade II may present with flu-like symptoms followed by a rash and can be spread through close person 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.

Pharmacies across LA County offer the vaccine. To locate a nearby pharmacy location with JYNNEOS vaccine, visit the Bavarian Nordic Vaccine Locator webpage. Individuals can also call their healthcare providers to inquire about receiving JYNNEOS. Public Health maintains a list of public vaccination sites  that carry the JYNNEOS vaccine which is updated frequently.

For more information on how to get the mpox JYNNEOS vaccine, call the Public Health Infoline at 1-833-540-0473, seven days a week, 8 a.m. to 8 p.m.