STI data and reports

STI recent trends

From 2023 to 2024, the number of new HIV diagnoses in San Francisco increased by 4%; the number of chlamydia diagnoses decreased by 25%, early syphilis diagnoses decreased by 36%, and gonorrhea diagnoses decreased by 3%.

San Francisco was one of the first urban centers to see declines in new HIV diagnoses. These decreases were due to citywide efforts to scale-up HIV testing and early and widespread HIV treatment, a strong linkage-to-HIV care program (provided by the SFDPH LINCS team), and access to syringes, condoms, and PrEP (pre-exposure prophylaxis for HIV) (source: see "References" below).

New HIV diagnoses declined by 55% from 326 in 2014 to 146 in 2024 (source: HIV Epidemiology Annual Report 2024 San Francisco).

In contrast, rates of syphilis, chlamydia, and gonorrhea increased each year from 2014 to 2018. There was a sharp decline in STI diagnoses in 2020 attributed to COVID-19 impacts on health care services. STI rates never returned to the levels seen in the years immediately preceding the introduction of COVID-19 and began to decline since the October 2022 release of citywide guidelines for doxycycline post-exposure prophylaxis (doxy-PEP) for STI prevention (source: JAMA: Doxycycline Postexposure Prophylaxis and Sexually Transmitted Infection Trends). Chlamydia and early syphilis rates in 2024 are the lowest seen since 2006 and 2007, respectively (with the exception of 2020). Doxy-PEP is less effective at preventing gonorrhea as compared to chlamydia and syphilis, reflected in a more limited decline in gonorrhea rates since 2022.

5-year comparisons in the number of cases are provided for each STI below, reflecting changes between 2020 and 2024. Comparisons should be interpreted within the context of disrupted health services and changes in health behaviors in 2020. More recent comparisons (changes between 2022 and 2024) better reflect STI trends in San Francisco than rates seen during the COVID-19 pandemic.

Syphilis trends

In 2024, 85% of new early syphilis cases in San Francisco were among men, the majority of whom identified as gay or bisexual, or reported having sex with a man.
From 2020 to 2024, there was a 49% decrease in total syphilis diagnoses in men (1,421 to 718) and a 4% decrease in total syphilis in women (160 to 153).
Between 2020 and 2024, there were 20 total congenital syphilis cases in SF, a 150% increase compared to the 8 cases in the prior 5 years (2015-2019).

Chlamydia trends

The number of chlamydia cases decreased by 26% (5,707 to 4,219) in San Francisco between 2020 and 2024.
Adolescent and young adult women experience disproportionate rates of chlamydial infection, more so among Black/African American youth. There are multiple factors that contribute to these persistent disparities.

Gonorrhea trends

Between 2020 and 2024, the number of gonorrhea cases increased by 17% (4,086 to 4,811) in San Francisco but has decreased by 8% since 2022.
In 2024, 70% of gonorrhea infections among males in San Francisco involved the rectum or pharynx (throat).

References

A graph showing trends and rates for chlamydia, gonorrhea, and early syphilis. Also shows number of HIV diagnoses. Years covered are 2014 to 2024.

STI monthly reports

2025

The monthly reports for January 2025 through June 2025 include errors in the Table 2 rates. All other information in each of those monthly reports is accurate as of the date of publication.

The monthly reports for January 2025 through November 2025 included only HIV rapid tests and 4th generation HIV tests in the total “Tests” count in Table 3. Starting in December 2025, the row for total “Tests” also includes pooled RNA tests.

2024

The monthly reports for January 2024 through November 2024 have been removed due to errors. The December 2024 report has been corrected and updated, still providing totals for 2024.