A colorized transmission electron micrograph shows two mature mpox (monkeypox) virus particles (pink) attached to the surface of an infected VERO E6 cell (blue/teal). The image was captured at the National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility (IRF) in Fort Detrick, Maryland. (National Institute of Allergy and Infectious Diseases/National Institutes of Health via Bay City News)

A second strain of monkeypox was reported in San Francisco by someone who came into contact with a carrier of the virus who had traveled internationally, the city’s Department of Public Health said Thursday. 

On Tuesday, the SFDPH confirmed the first case of clade I mpox in a resident. The person was not vaccinated against mpox but is improving after being hospitalized, the department said. 

There are two types of mpox, clade I and clade II. An outbreak of the virus in the city in 2022 was caused by clade II; this most recent case is from clade I. Both types are mainly spread through close skin-to-skin contact such as sexual activity.

“While anyone can get mpox, most reported cases are among gay, bisexual, and other men who have sex with men, as well as transgender persons who have sex with men,” SFDPH said in a Thursday press release. 

As of now, public health officials do not know if clade I is more severe than clade II, but said cases of clade I in the United States are currently rare.

According to SFDPH, symptoms include fever, swollen lymph nodes and fatigue, followed by a rash that looks like pimples or blisters.

There is a vaccine available against mpox and the city is encouraging risk groups to avail themselves of it, especially people planning on traveling to Europe or Africa, where clade I has been reported. 

SFDPH officials said the vaccine is safe even for immunocompromised people such as those living with HIV or taking immune-suppressing medications. The vaccine is not recommended for people who have previously been infected by mpox.  

The vaccine is available through health care providers and local pharmacies. For uninsured people or those who are otherwise having difficulty getting the vaccine, a list of helpful locations in San Francisco can be found at sf.gov/mpox.

Katy St. Clair got her start in journalism by working in the classifieds department at the East Bay Express during the height of alt weeklies, then sweet talked her way into becoming staff writer, submissions editor, and music editor. She has been a columnist in the East Bay Express, SF Weekly, and the San Francisco Examiner. Starting in 2015, she begrudgingly scaled the inverted pyramid at dailies such as the Vallejo Times-Herald, The Vacaville Reporter, and the Daily Republic. She has her own independent news site and blog that covers the delightfully dysfunctional town of Vallejo, California, where she also collaborates with the investigative team at Open Vallejo. A passionate advocate for people with developmental disabilities, she serves on both the Board of the Arc of Solano and the Arc of California. She lives in Vallejo.