Dr. Ina Park: Syphilis on the rise
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April 14-20 is Sexually Transmitted Infections (STI) Awareness Week, bringing attention to recently-published data showing that cases of syphilis increased by nearly 80 percent between 2018 and 2022, reaching levels not seen since 1950.
On April 12, 2024, SciLine interviewed: Dr. Ina Park , a professor of family and community medicine at the University of California, San Francisco. See the footage and transcript from the interview below, or select ‘Contents’ on the left to skip to specific questions.
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Introduction
[0:00:15]
INA PARK: Hi, I’m Dr. Ina Park. I’m a professor at the University of California, San Francisco School of Medicine, in the departments of family medicine as well as OBGYN. I’m a medical consultant for the CDC, so I write their treatment guidelines as well as their recent 2024 guidelines for the diagnosis of syphilis.
Interview with SciLine
What can you tell us about recent trends in these rates of sexually transmitted infections?
[0:00:37]
INA PARK: Before the pandemic, we were seeing steady increases and in 2019, the CDC had announced this is the most number of STIs we’ve ever had reported to us, you know, at the CDC in the United States. Then the pandemic hit, and we did see a decline because people simply stopped testing and screening for them, and we had a national testing shortage. But gonorrhea and syphilis bounced right back. And right now, the biggest increases we’re seeing are with syphilis. So, in the past five years, we’ve seen an 80% increase in syphilis cases—so, over 207,000 in the US, and we’ve seen an almost 200% increase in cases of syphilis in babies.
What factors have led to the current rise in STIs?
[0:01:32]
INA PARK: We can’t really just blame one factor in particular, but it’s really a confluence of issues that have led to this sort of perfect storm. What we’re seeing, you know, epidemic increases. And one of them is dating apps. And so—I don’t want to throw any particular dating apps under the bus—but dating apps have made it so much easier for people to hook up for casual sex. And one thing that they’ve also done is they’ve allowed for the mixing of sexual networks. Whereas somebody who used to only be in these sort of lower-risk, lower-prevalence sexual networks can dip their toe into a higher-risk network and not even realize it. Because, you know, the apps are really based on finding someone sometimes, like where you actually happen to be located geographically at that time. And it’s not necessarily related, you know, to, for example, only the people that you’re going to meet at your local bar. The other thing is that depending on what part of the country you’re in, the substance use epidemic in particular, crystal meth, has a huge intersection with syphilis, especially in women and especially in the West. Now, I’m not saying that that’s not an issue in other parts of the country. But in the West, about a third of the women with syphilis reported, you know, use of crystal meth. And so, the other thing is that, in general, I will say that the fear of HIV is much less now than it was, you know, in the 80s and early 90s, when we didn’t have effective treatment. So, now we have effective treatment for HIV, where people who are taking it are no longer able to transmit the virus to their sexual partners. That’s the concept of undetectable equals untransmittable or u equals u. And then there’s also HIV PrEP, or pre-exposure prophylaxis. So, HIV-negative people don’t have to fear HIV. So, if you’re not fearing the sort of granddaddy of STIs, which is HIV, then, you know, the other STIs just maybe don’t seem, you know, quite as daunting. And, you know, perhaps, you know, condom use is, you know, not in such a high priority when HIV is sort of off the table as a risk.
What does it mean that there has been a 200% increase in syphilis infections in babies?
[0:03:50]
INA PARK: That is equating to about 3700 cases of syphilis in babies, and almost 300 of those babies are actually still born or died in the first 30 days of life. And, you know, most of those deaths—nine out of 10 of those deaths—were actually completely preventable.
How is syphilis transmitted to a baby during pregnancy?
[0:04:15]
INA PARK: Many infections can be contracted from mother to child during pregnancy, and that includes infectious diseases like HIV and syphilis. So, you know, as many of us who might be listening to this interview know, the placenta is a direct source of nutrition as well as, you know, blood supply, oxygen supply to the fetus. And so, if the mother is happening to harbor an infection that can go directly to the baby through the placenta, and syphilis is one of those infections where that can be directly passed just through blood-to-blood contact.
How do the consequences of syphilis in adults compare to those experienced in babies?
[0:05:00]
INA PARK: Adults who have syphilis may have no symptoms at all. And so, you might just say, well, that’s just, you know, it’s sort of an annoyance or a nuisance that I happen to have this STI. But, you know, obviously if untreated, syphilis actually can lead to longer-lasting neurological damage, it can lead to cardiovascular damage. And that’s if it goes untreated for many years. But in babies, you can have an infection of a very short duration—even just a couple of months—and you can get serious organ damage to the liver, to the brain, to the teeth, to hearing, you can have you know, permanent hearing loss, permanent damage to the bones.
What can you tell us about demographic and geographic differences in the rates and risks of syphilis?
[0:05:42]
INA PARK: The epidemic looks so different depending on what part of the country you’re in. And while really women of all races and ethnicities are affected, we see the greatest rates in women of American Indian and Alaska Native Heritage. And then after that would be women who identify as non-Hispanic Black or African American. But again, it’s really affecting women of all races. But, as I mentioned, the epidemic is different. So, in the West, about a third of women who have syphilis, who are of that age where they could become pregnant, actually report using crystal meth. And so there’s a huge intersection, as you can see, with the substance use epidemic, but that’s not really the case in the south or the northeast. And in those cases, you know, issues like poverty, for example, or incarceration and lack of access to care are more of an issue than substance use. So, you can’t really use a one size fits all approach because the epidemic is really different in different regions of the country.
What public health measures could help alleviate the current syphilis epidemic?
[0:06:55]
INA PARK: I think it’s so important for, you know, everyone out there who’s listening, especially providers, people who might work with health departments, to really be encouraging access to testing as much as possible. And so if we think about our public health safety net, increasing access to testing services, and making them free or low-cost and really low barrier, because I’m not sure if everyone is going to be familiar, but we almost eliminated syphilis in this country, so many providers don’t recognize it, and it can often be asymptomatic and can go for years that way. So, the only way we’re going to be able to identify cases, you know, on a national level is to be doing a massive push for testing.
What can individuals do to reduce their risk of contracting and transmitting STIs?
[0:07:43]
INA PARK: The only way you can completely avoid STIs is to stop having sex, and I never give that advice. So, you know, we want people to keep having sex. But the way to do it, I said, I suppose more safely would be obviously limiting your number of partners and testing in between partners so that you know you’re entering a new partnership without an STI onboard. And then this is sort of a technique that I think not many of us are taught in school and were taught sex education is that if you have multiple partners at the same time, in a short amount of time, that’s actually a really efficient way to spread STIs. So, having one partner, then breaking up with them, then getting another partner, and not sort of going back and forth between partners is also a really good way to avoid spreading STIs in the greater community.
What can pregnant people do to reduce the risk of transmitting syphilis to their child?
[0:08:40]
INA PARK: Syphilis is often asymptomatic or silent, so pregnant people might not even know that they have the infection. So, what lots of states are doing is recommending testing three times in pregnancy. So that’s not every state—every state does recommend testing for syphilis at the first prenatal visit. But some states are now recommending also testing at 28 weeks, you know, which is about seven months of pregnancy, and then again at delivery. So, it’s giving us lots of chances to either, you know, catch syphilis before the baby is born. Or if you’re going to do that screening at delivery, then you’re catching the infection, you know, before the baby leaves the hospital, so you can get treatment on board right away. And in many cases, that can, you know, help the baby not suffer those consequences of syphilis and even save the baby’s life. So again, we’re back to testing, and testing, and testing some more.
What can you tell us about the use of antibiotic doxycycline after sex to prevent STIs?
[0:09:41]
INA PARK: There’s a really exciting intervention called doxycycline as post-exposure prophylaxis, and it’s known by the name DoxyPEP, and so that is taking 200 milligrams of doxycycline which, by the way, is an antibiotic that many people have likely heard about because it’s been around since the late 50s. And it’s been used for other things, like malaria prophylaxis, as well as for respiratory infections and acne. So, you take 200 milligrams up to 72 hours after having condomless sex—so that can be oral sex, anal sex, or vaginal sex—and it is highly effective at reducing syphilis. So, in some of the studies, there’s been three now that have been done. It’s almost 80% effective at reducing new cases of syphilis as well as chlamydia. It’s a little bit less effective against gonorrhea. And we’re talking more in the, you know, 50 to 60% range. But it’s a really exciting intervention, I think, either way, when we look at reduction in risk for the three bacterial STIs that we most commonly report on to the CDC.
