JOHN YANG: According to the CDC, the number of syphilis cases in the United States is the highest it's been since the 1950s.

Ali Rogin looks at what's behind this surge of this sexually transmitted infection or STI and what public health officials are doing about it.

ALI ROGIN: Syphilis was close to being eradicated in the U.S. in the 1990s.

But in the decades since funding for prevention and treatment has stagnated, and the number of cases has risen steadily.

According to the latest report from the CDC cases of syphilis shot up 80 percent from 2018 to 2022 alone.

Dr. Philip Chan is the Chief Medical Officer for Open Door health, a center for LGBTQ plus patients in Rhode Island, and an associate professor at Brown University.

Dr. Chan, thank you so much for joining us.

Why are syphilis cases on the rise?

And should we be concerned about this?

DR. PHILIP CHAN, Brown University: Syphilis, unfortunately, has been increasing for a couple of decades here in the U.S. as largely gone unnoticed.

It's increasing now and circulating among the cisgender heterosexual population.

And we just aren't testing enough.

And we don't have the infrastructure needed to address this increase not only in syphilis, but also other STIs.

ALI ROGIN: As you mentioned, cases arising among cisgender people, particularly cisgender women and heterosexual people.

Why are we seeing the increases in those populations in particular?

PHILIP CHAN: I think the simplest has gotten a foothold in that population, and especially among populations that have been marginalized, a little bit more African American, black, Hispanic, Latinx communities, and we're just seeing spread because we aren't testing enough.

Congenital syphilis especially is a huge concern.

It can cause really significant complications for the unborn baby up to and including death.

A lot of women from especially underserved communities aren't getting prenatal care.

It is recommended and required in many states that pregnant women do undergo syphilis testing.

So the fact that we're missing these cases the fact that we're seeing congenital syphilis I think shows us that a lot of folks aren't getting the prenatal care that they need.

ALI ROGIN: How did the COVID 19 pandemic disrupt STI treatment and detection of syphilis cases?

PHILIP CHAN: What we saw during the pandemic with a lot of clinics closed, while the staff were reassigned to deal with COVID-19, in a lot of cases went undiagnosed.

I think on the other hand, a lot of folks had less sex potentially.

So we may not have been seeing a lot of transmission.

But there was definitely some transmission that was going on that was unrecognized.

ALI ROGIN: The rising cases in the last decade has coincided with a drop in funding for STI screening and prevention, Congress cut $400 billion for disease investigators as part of the debt ceiling negotiation last year, how is this going to affect the existing resources for testing and detection?

PHILIP CHAN: I think the health departments in all states are really critical centers for addressing the STI epidemic.

They're responsible for communicating with partners for disseminating funding for contact tration, and partner notification services.

So this reduction in funding has really been harmful to the health departments.

We definitely need more infrastructure.

We need more funding.

We need more resources to address this increase in STIs.

ALI ROGIN: And since last year, there's also been a shortage of penicillin, which is the most effective drug used to treat syphilis in adults and the only drug that can treat pregnant women to prevent congenital syphilis.

How are people dealing with that shortage?

And and will the shortages make the existing problem even worse?

PHILIP CHAN: So the good news is that syphilis remains highly sensitive to penicillin, which is a generally a common antibiotic.

Unfortunately, you do need a little bit of a long acting formulation.

At this time, we are having a shortage of benzathine penicillin, the formulation that we use to treat syphilis, and specifically in pregnant women.

What we're doing is really prioritizing people who are pregnant for the benzathine penicillin.

We're using alternative antibiotics for other people.

It's not great, but it's what we're doing while there's a shortage.

ALI ROGIN: Yeah, we're aware that there are efforts to use a drug called doxycycline as post exposure prophylaxis, how effective is that?

PHILIP CHAN: This is one of the most exciting things in the field of STIs.

A lot of us are really hopeful that it's going to be a game changer as we talk about addressing STIs.

So doxycycline is a pretty common antibiotic.

And there's studies now that show that it's really effective in preventing syphilis, Chlamydia, and gonorrhea.

So we expect some CDC recommendations in the near future, but it's going to be recommended to prevent STIs, the data is strongest in gay bisexual other men go sex with men and transgender women.

We're hoping it's really going to be a game changer in preventing and addressing the STI epidemic.

ALI ROGIN: He mentioned a few other STI is gonorrhea and chlamydia.

Interestingly, gonorrhea is down slightly for the first time in a decade and Chlamydia cases have remained stable.

If these infections are resulting from those same sexual practices and health issues that we've already discussed.

Why are those other two rates stabilizing while Syphilis is on the rise?

PHILIP CHAN: Well, I think it's good news.

I think it also remains to be seen.

This is a single data point from last year the data that we have, but reassuringly these STIs have remained stable.

But I think it remains to be seen whether or not this trend continues.

I do think all these STIs are transmitted slightly differently, slightly different attack rates in terms of being transmitted to other people.

And I think for things like gonorrhea especially we see slightly less attack rates and potential for transmission compared to a committee of specialists.

ALI ROGIN: Dr. Philip Chan, Chief Medical Officer for Open Door Health and associate professor at Brown University.

Thank you so much for your time.

PHILIP CHAN: Thank you for having me.