San Francisco saw increased cases of sexually transmitted diseases for the eighth consecutive year in 2013.
According to preliminary numbers from the city's public health department, chlamydia, gonorrhea, and early syphilis continued their upward climb last year.
"Clearly, we are concerned there continues to be increases," said Deputy Health Officer Dr. Susan Philip, the director of disease prevention and control in the health department's population health division. "We believe the public needs to be aware of that."
Overall reported chlamydia increased from 4,874 in 2012 to 5,089 cases in 2013, a 4.4 percent year-over-year increase. Male rectal chlamydia also increased in 2013 from 1,081 to 1,167 cases for an 8 percent annual increase from 2012.
Reported gonorrhea cases increased 1.6 percent from 2,481 in 2012 to 2,521 in 2013. Additionally, rectal gonorrhea among men also increased from 780 cases to 794 cases, marking a 1.8 percent increase.
After declines in early syphilis seen in 2008, early syphilis continues to increase. In 2013, reported early syphilis increased by 13.9 percent from 890 cases in 2012 to 1,014.
"I don't know if this is a new normal. I am not sure we are going to expect rates are going to continue to increase," said Philip.
The health department is committed to working "diligently" and partnering with the community to decrease the rates, added Philip, though she acknowledged it is an uphill fight.
"There is no silver bullet for this," said Philip. "Until we get vaccines for these STDs, we are not going to have an easy fix."
The final 2013 numbers won't be known until later this year, although the majority of STD cases remain among men who have sex with men, said Philip.
"It does look like the increases are primarily, again, among MSM," Philip told the Bay Area Reporter in a phone interview last week.
According to a report based on 2012 data the health department's STD Control Section released last October, of the 64,681 MSM estimated to live in San Francisco one out of 79 was infected with early syphilis.
One out of 34 MSM was infected with gonorrhea, according to the report, and one out of 36 was infected with chlamydia.
Compared to their heterosexual counterparts, gay and bisexual men's risk of early syphilis is 117.0 times higher. Their risk of gonorrhea is 8.6 times higher compared to heterosexual males. And MSM's risk of chlamydia is 27.2 times higher compared to heterosexual males.
Nationally, the Centers for Disease Control and Prevention estimate that MSM account for three quarters (75 percent) of all primary and secondary syphilis cases. In 2012 there were 15,667 reported cases of early syphilis, with the rates of primary and secondary syphilis rising 11.1 percent. The increase was seen solely among men, particularly among MSM.
"The ever-increasing rates of sexually transmitted diseases continue to threaten the health and well-being of millions of Americans, particularly youth and men who have sex with men," stated William Smith, executive director of the National Coalition of STD Directors. "The long-term consequences of these diseases impact the health of the individual, burden our larger health care system, and drastically hinder our continued fight against HIV and AIDS."
Divergence Seen in STD and HIV Rates
Health officials have long worried that increased STD rates could lead to increased HIV rates, as having an STD increases a person's susceptibility of contracting HIV. But HIV rates have remained relatively stable in San Francisco, with new HIV infections steadily declining since 2006.
A slight uptick in HIV cases among MSM in 2012, however, has local health officials concerned and closely watching to see if it was just a one-time blip or a sign that HIV may now be mirroring the STD increases. So far there is no indication that the higher STD rates are behind the upturn in HIV numbers from two years ago.
"What we can say is there has been increasingly a separation in San Francisco, certainly, between HIV infection rates and STD infection rates," said Philip. "From all estimates HIV does not seem to be rising at the same rate as those STDs which concern us."
There is growing consensus that changes in how gay and bisexual men practice safe sex are driving the rising rates of STDs not only seen in San Francisco but also across the country and in other nations. Many of the strategies gay and bisexual men are adopting are focused on stopping HIV infection and do not work in terms of protecting them from STDs.
"I would like to be able to do more investigation into that, but it does seem to be consistent with what we are seeing in San Francisco, this idea that gay men are really focusing primarily on HIV prevention and may not be as concerned with having gonorrhea and syphilis," said Philip. "It might be one explanation for what we are seeing in San Francisco with STD rates continuing to rise."
In a December article titled "Syphilis in the Modern Era - An Update for Physicians" that Philip co-authored with colleagues from City Clinic and her predecessor Dr. Jeffrey D. Klausner, now at UCLA, the medical professionals wrote that the "syphilis epidemic among MSM" has been linked to "a decrease in safer sex practices secondary to HIV prevention fatigue, antiretroviral treatment optimism, and an increase in recreational drug use, especially methamphetamines and erectile dysfunction medications."
Another factor they cite is gay and bisexual men adopting harm-reduction strategies like serosorting - having selective unprotected sex with partners of the same HIV-serostatus - and oral sex to decrease their risk of HIV transmission.
Such practices "can facilitate syphilis transmission," states the article, co-written by Dr. Stephanie Cohen, medical director of City Clinic, and Dr. Joseph Engelman, who is on the medical staff at City Clinic.
The authors also point to the latest focus in HIV prevention on promoting the early use of antiretroviral medications in order to suppress viral load in individuals and the community as a way to prevent HIV. They note that the biomedical intervention does not hinder syphilis transmission.
"This may partially explain the divergence between HIV and syphilis rates among MSM that is occurring in some municipalities," states the article. "If other biomedical HIV-prevention strategies, for instance pre-exposure prophylaxis, become more widespread, the divergence between syphilis and HIV epidemiology may further widen."
Other contributing factors include the ease of meeting sex partners online and people living with HIV longer, increasing the number of men at risk for syphilis and other STDs.
Steps people can take to reduce their STD risk, said Philip, include using condoms and reducing their number of sexual partners. They should also seek treatment at the first sign of an STD infection, she added, and inform their sexual partners they could be at risk.
Sexually active gay and bisexual men should get tested for STDs every three to six months. Studies have shown that more MSM in San Francisco report getting tested more frequently than their counterparts in other cities.
"We do think we are getting the message out," said Philip.