Background
In August 2025, so far, there has been an average of 13 clade II mpox cases per week (compared to 7.9 and 4.0 cases per week in July and June, respectively). While this increase has mostly occurred in the San Francisco Bay Area, travel between counties and sexual exposure associated with attending clubs, venues, parties, or other events is common. Most cases have been among gay, bisexual, and other men who have sex with men and their social networks. All of these cases have been clade II mpox, which has been circulating in California since 2022.
As a reminder, there are currently ongoing outbreaks of clade I mpox in sub-Saharan Africa. Sporadic travel-associated cases have since been identified in the U.S. and other countries. At this time, people who have traveled to countries with clade I mpox outbreaks and their close contacts are most at risk. All of the mpox cases in California in 2025 so far have been clade II.
Recommendations
Given this recent increase in cases, providers are reminded to incorporate mpox evaluation and prevention into routine sexual health care, including when people are being tested for sexually transmitted infections (STIs) or receiving HIV pre-exposure prophylaxis (PrEP) or post-exposure prophylaxis (PEP), doxy PEP, or treatment for HIV and other STIs.
Clinical Recognition
Mpox should be considered as a differential diagnosis in sexually active patients with rash, lesion(s), or proctitis. Testing is still warranted among vaccinated persons (or those with previous mpox infection) if compatible signs and symptoms (PDF, 1.2MB) are present. Symptoms among people with prior mpox infection or vaccination are more likely to be mild.
Risk assessments including recent sexual practices and international travel history (for clade I mpox exposure risk) can help guide clinical decision-making.
Testing
Mpox testing is via polymerase chain reaction (PCR) using lesion swabs, available through most commercial laboratories and some local public health laboratories.
If clade I mpox is suspected (e.g., an international traveler or a contact of an international traveler in the prior 21 days), promptly notify your local health department and the CDPH Viral and Rickettsial Disease Laboratory (VRDL) to arrange expedited, comprehensive testing: (510) 307-8585 or VRDL.submittal@cdph.ca.gov.
Treatment
There is no treatment specifically approved for mpox. Most cases of mpox are mild and resolve with supportive care and pain management.
For patients with severe or complicated mpox infections, providers are advised to consult their infectious disease providers, CDPH, and the U.S. Centers for Disease Control and Prevention (CDC). Certain therapeutics may be recommended for these patients, as well as for patients with risk factors for disease progression (e.g., severe immunocompromise).
Vaccination
Mpox vaccination with two doses, at least 28-days apart, is recommended for individuals who may be at risk for mpox. This includes patients who still need second doses or who may not have received vaccine at the start of the 2022 outbreak.
Providers should consider incorporating assessments for mpox risk and vaccination status at all routine sexual health visits. To simplify assessment and improve community vaccination coverage among those at increased risk of exposure given current outbreak data, CDPH recommends the mpox vaccine for any person who:
Is gay, bisexual, or other man who has sex with men or
Is transgender, nonbinary, or gender-diverse or
Has HIV, or is taking/eligible for HIV PrEP or doxy PEP or
Was exposed to someone with mpox in the last 14 days or
Is planning to travel to sub-Saharan Africa or a country with a clade I mpox outbreak and anticipates sexual or intimate contact while traveling or
Anticipates attending a commercial sex event or venue (like a sex club or bathhouse) or
Has a sex partner with any of the above risks or
Requests mpox vaccination, even if they have not disclosed any risks listed above
While no vaccine is perfectly effective, mpox vaccination remains the best strategy to minimize the risks of acquiring mpox and protect against complications including severe illness, hospitalization, and death.
Vaccination may be especially important to prevent severe disease in patients with HIV or other immunocompromise.
Vaccines are available at many chain pharmacies and certain clinics—see Mpox Vaccine Locator.
As of 2025, CDC and the Advisory Committee of Immunization Practices (ACIP) guidelines do not recommend more than two vaccine doses (boosters) or vaccination for people who have recovered from previous mpox infection.
Resources