SF Saw Drop in Syphilis Cases in 2016, Rise in Other STDs

For the first time since 2007, San Francisco last year saw a decline in cases of early syphilis, according to preliminary year-end data for 2016.

Yet the city also reported double-digit increases in both chlamydia and gonorrhea cases, based on the early totals from the health department's monthly sexually transmitted disease report issued February 16. The final numbers won't be known until later this year.

The initial report showed that, compared to 2015, early syphilis declined moderately from 1,205 to 1,139 cases in 2016. Total syphilis cases also decreased from 1,394 in 2015 to 1,340 last year. Those numbers still marked significant increases in the venereal disease from 2007, when there were 202 reported cases.

The decline in syphilis rates was seen across all races except Asians/Pacific Islanders, who had a rate increase of 16.5 percent (98 early syphilis cases in 2015, 114 in 2016), according to the report.

STD prevention officials suggested that the modest 3.9 percent reduction in the total number of reported syphilis cases among adults may reflect a biannual cyclical fluctuation in syphilis morbidity.

"The levels may go up and down slightly every couple of years, but it is early and we are looking into what that means," said Deputy Health Officer Dr. Susan Philip, the director of disease prevention and control?in the health department's Population Health Division. "We are going to look more closely before we say we have made the turn on syphilis. We don't want to declare victory just yet, there is still a lot of work ahead of us."

As for chlamydia cases, they increased by 11.8 percent (from 7,233 to 8,086 cases) between 2015 and 2016, with a steeper increase of 19.2 percent in male rectal infections (from 1,773 to 2,113 cases). There was also a 7.8 percent increase of cases among women aged 15 to 25.

Gonorrhea increased by 21.9 percent last year, from 4,263 to 5,196 cases. Cases among women aged 15 to 24 increased 32 percent from 146 in 2015 to 193 in 2016.

Rectal gonorrhea cases among men increased almost as steeply in 2016 as in 2015, by 24.1 percent, from 1,135 to 1,409 cases, noted the report.

Hispanics, at 25 percent, accounted for the biggest increase in rates of chlamydia, while whites, at nearly 26 percent, had the highest increase in gonorrhea rates last year.

Overall rates of STDs in the city have been on the rise for more than a decade. Health officials are unsure of the exact reasons for the increases, though a main factor has been sexual practices that eschew the use of condoms.

Last year the health department rolled out a social marketing campaign encouraging gay and bisexual men in particular to use condoms in order to prevent themselves from contracting STDs. Gay and bi men who are sexually active should also get tested for STDs every three months.

Health officials have also been advising gay and bisexual men using PrEP to remain HIV-negative not to forgo condoms because the drug does not protect them from STDs. But a study released during last week's Conference on Retroviruses and Opportunistic Infections is calling that advice into question.

It suggested that PrEP usage by gay and bi men who routinely get screened for STDs could lead to significant reductions in some sexually transmitted infections, even when condoms aren't used.

The modeling study, from researchers at Emory University's Rollins School of Public Health, determined that chlamydia infections would fall by 40 percent and gonorrhea infections by 42 percent over the next decade in the U.S. if 40 percent of PrEP-eligible men who have sex with men started taking the once-a-day pill of Truvada and were tested for STDs biannually. The researchers determined the STD decreases would occur even with a 40 percent reduction in condom use.

"Clinicians have a critical role to perform the recommended STI screening and treatment, as incidence could increase if PrEP is delivered without those services," wrote lead author Samuel Jenness, Ph.D., an assistant professor of epidemiology at Emory.