STI Surveillance, 2023: Key Trends

intro--3rd-edition[00:00] Intro & 3rd Edition

Hello everyone. My name is Meena Ramchandani. I’m an infectious disease physician at the University of Washington in Seattle. This podcast is dedicated to an STD [sexually transmitted disease] literature review for health care professionals who are interested in remaining up-to-date on the diagnosis, management, and prevention of STIs.

Hi everyone. In this episode, we’re going to review the CDC’s 2023 STI surveillance report, which was released in November 2024. 

But first, I have an exciting announcement: the 3rd Edition of the National STD Curriculum just launched in April. All the Lessons and Question Bank topics have been reviewed and updated so you can earn free continuing education credits, and this is even if you earned those credits on a previous edition. The site looks great. It’s very easy to use, so I do encourage you to take a look and learn more about the management of STIs. Now, turning back to the topic for this episode.

Centers for Disease Control and Prevention (CDC). Sexually Transmitted Infections Surveillance, 2023. Atlanta: U.S. Department of Health and Human Services; November 2024. [CDC]

This is a 2023 STI surveillance report. Overall, there were more than 2.4 million STIs in the U.S. in 2023, and a big highlight of this report is the promising sign that the epidemic actually might be slowing. From 2022 to 2023, the number of STIs decreased by 1.8%. And so, we’re going to review trends seen for chlamydia, gonorrhea, and syphilis cases in the U.S. in this episode.

syphilis[01:26] Syphilis

Let’s start with talking about syphilis. Syphilis did increase in the U.S., but only by 1%, which is a lot less compared to previous years. Overall, there were about 209,000 cases of syphilis in 2023. Now, the number of primary and secondary syphilis cases, and this is where patients are symptomatic, went down by 10%. This is the first substantial decrease in primary and secondary syphilis since 2001. Now, it might also suggest that the small increase in overall cases of syphilis might be due to increased screening. So, public health programs and other innovative strategies to increase STI testing, including education and awareness, seem to be working. 

MSM (or men who have sex with men) continue to be disproportionately impacted by syphilis in the U.S. In 2023, MSM accounted for about one-third of all primary and secondary syphilis cases. Now, the good news is that the cases of primary and secondary syphilis decreased about 13% among MSM, and this is the first time this has occurred in over 15 years. Decreases in cases of primary and secondary syphilis were observed in MSM both with and without HIV. 

In 2023, congenital syphilis cases continued to increase, but the rate of increase seems to be slowing. There was a 3% increase from 2022 to 2023 and this is compared to a 30% annual increase in prior years. So, from 30% down to 3% increase. And so, we still have work to do because high congenital syphilis cases do persist and there is increasing rates, but it does seem to be improving overall. There were around 3,800 cases of congenital syphilis and this included 279 stillbirths and infant deaths. Almost all jurisdictions reported at least one case of congenital syphilis in the U.S. in 2023.The rate of syphilis increased by almost 7% among women ages 15 to 44 years old. Black or African American birth parents represented 29% of congenital syphilis cases, and this was despite being only 14% of the live births. The highest rate of congenital syphilis was among parents who were American Indian or Alaska Native, and this was followed by those who were Native Hawaiian or other Pacific Islander. From 2022 to 2023, the greatest increase in the rate of congenital syphilis was among parents who were Hispanic or Latino. It’s important to point out these differences because they may reflect access to quality sexual health care in these communities. 

If you’re interested in hearing more about missed opportunities in congenital syphilis and syphilis in pregnancy, including potential solutions, please refer to our episode from February 2025 with summaries of oral presentations from IDWeek 2024. 

The CDC recommends health care providers offer syphilis screening to all sexually active people 15 to 44 years of age in counties with a high rate of syphilis among women of reproductive age. This is part of the Healthy People 2030 goal. There is a map and data table available online to see if you should offer syphilis testing to this group in your practice area. 

So, overall, STI prevention and public health seems to be working with regards to syphilis for the first time in many years in the U.S. Syphilis did increase in 2023, but by only 1%, and primary and secondary syphilis did decline for the first time since 2001. There are increases in congenital syphilis, but the rate does seem to be slowing and hopefully will sustain in years to come. Further work, public health, and research needs to be done in this area to address the syphilis epidemic in the U.S. 

gonorrhea[05:20] Gonorrhea

Let’s turn to talking about another pathogen. There were around 600,000 cases of gonorrhea in 2023. The rates of gonorrhea decreased by 7%, which is encouraging, and this is the second year in a row in which gonorrhea rates have declined. Now, prior to that, rates of gonorrhea had increased yearly since 2009. 

The decrease in rates of gonorrhea were most pronounced among women, with a 14% decrease since 2022. Rates also decreased among men by 3%. While decreasing rates are encouraging, there is a possibility that the decline is not only due to a decrease in new infections but also potentially due to reduced screening, as gonorrhea can be asymptomatic. So, the less people you screen for infection, the less cases you’re going to find. The rate of gonorrhea was higher among men compared to women. The data from the STI Surveillance Network suggest that about half of the gonorrhea cases occurred in MSM. The report found that those who were 20 to 24 years old had the highest rate of reported cases of gonorrhea in both men and women. 

The South of the U.S. had the highest rate of gonorrhea at 206 cases per 100,000 persons, and this was followed by the West, the Midwest, and then the Northeast. In all of these geographic areas, rates decreased from 2022 to 2023, except in the Northeast, where rates actually increased from the prior year. 

Black or African American persons represented 39% of gonorrhea cases despite being 12.6% of the U.S. population. Differences were also seen in American Indian or Alaska Native persons with regard to gonorrhea cases relative to their proportion of the population. Again, as I said before, differences likely reflect access to quality sexual health care in these communities as well as differences in sexual network characteristics.

The rates of gonorrhea decreased for a second year in a row, which is encouraging, and fell to below pre-COVID-19 pandemic levels. While this might be due to a decrease in new infections, we have to remember it could also be due to reduced screening and STI testing. 

chlamydia[07:35] Chlamydia

Let’s turn to chlamydia infections. There were 1.6 million cases of chlamydia, which represents a 9% decrease since 2019. From 2022 to 2023, the rates of chlamydia were stable, although the rate increased among men by about 1% and it decreased among women by about 2%. The number of cases of chlamydia may be lower than expected due to decreased screening coverage, as these infections are often asymptomatic. 

The South of the U.S. had the highest rates of chlamydia infections, followed by the Midwest. What the report found is that the rates of chlamydia were highest among adolescents and young adults, with 56% of all cases among persons ages 15 to 24 years. Among both men and women, Black or African Americans had the highest rate of chlamydia cases, and this was followed by American Indian or Alaska Natives in 2023. The greatest number of reported chlamydia cases, and that’s a little bit different than the rate, was among Black or African Americans, followed by Whites in the U.S. 

summary[08:41] Summary

To conclude, I’d like to summarize some key points from this session:

1. Over 2.4 million cases of syphilis, gonorrhea, and chlamydia were reported in 2023, and this was a 1.8% decrease in STIs from 2022. 

2. There was a 7.2% decrease in gonorrhea, stable trends in chlamydia, and an increase in total syphilis. When I say “increase in total syphilis,” I mean all cases of syphilis including all stages and congenital syphilis, by about 1%.

3. There were over 3,800 cases of congenital syphilis, including 279 congenital syphilis stillbirths and infant deaths.

4. So, these are promising signs that the epidemic might be slowing, but continued efforts for prevention and care will be needed, especially for priority populations.

credits[09:30] Credits 

This podcast is brought to you by the National STD Curriculum, the University of Washington STD Prevention Training Center, and is funded by the Centers for Disease Control and Prevention. Transcripts and references for this podcast series can be found on our website, the National STD Curriculum at www.std.uw.edu. Thank you for listening and have a wonderful day.