Summarizing STI Statistics: February 2024

At the end of January, the Centers for Disease Control and Prevention (CDC) released statistics outlining the number of sexually transmitted infections (STIs) that occurred in 2022. Many of the related headlines read similar to “Syphilis Is Soaring in the U.S.” While this is true; there is more to the story. This post updates the statistics shared in “Summarizing STI Statistics and Innovations” and explores less splashy STI news. One thing to be mindful of is to interpret the 2022 statistics cautiously because of the disruptions in medical care during the COVID-19 pandemic.

Syphilis Cases Continue to Increase

The number of reported syphilis cases increased by 17 percent from 2021-2022, bringing the total number of cases in 2022 to 203,500. There were an additional 3,755 cases of congenital syphilis, a 30.6 percent increase from 2021-2022. The definition of congenital syphilis includes any case of syphilis acquired before a child is born as well as stillbirths that occur after the twentieth week of gestation when the pregnant person had untreated or inadequately treated syphilis at the time of delivery. Although congenital syphilis can cause severe health problems and even death, some cases can be mild, but still require treatment.

For syphilis, treatment specifics depend on the stage of the disease, but generally involve one or more penicillin injections. Congenital syphilis is also treated with penicillin and can be prevented by treating the pregnant person with penicillin during pregnancy. Many states require prenatal screening for syphilis, but this screening can only be accomplished if a pregnant person receives adequate prenatal care. Unfortunately, the rise in syphilis, and especially congenital syphilis, shows that many people are slipping through the cracks of our STI testing and medical infrastructure.

Gonorrhea and Chlamydia

Although more people received syphilis diagnoses compared to 2021, gonorrhea and chlamydia infections were much more common. The 1,649,716 chlamydia cases in 2022 accounted for two-thirds of all reported STIs. These numbers are similar to chlamydia diagnoses in 2021, although chlamydia has the distinction of being the only reportable, bacterial STI that has seen a marked decrease in cases compared to 2018.

Gonorrhea was the second most commonly reported bacterial STI with 648,056 diagnoses, which made up a quarter of all reported STI cases. There were almost 9 percent fewer gonorrhea cases in 2021 than in 2022; but looking at a longer timeframe, the number of cases is higher than it was five years ago.

Another consideration with gonorrhea is emerging antimicrobial resistance. The term “antimicrobial resistance” describes when disease-causing microbes gain the ability to ward off the effects of the medications that are supposed to kill them. This can make it difficult or impossible to treat a person who acquires a bacterial, viral, or fungal infection or a parasite. Although antimicrobial resistance is a natural process, human behavior can speed up the process.

Gonorrhea has proven it is quite good at adapting to resist available antibiotics. Around the turn of the millennium, the United States began seeing evidence of gonorrhea developing antimicrobial resistance to one type of antibiotic. By the mid-2000s, only one class of antibiotic remained a CDC-recommended treatment for gonorrhea. Fortunately, despite the proportion of cases that demonstrate some amount of decreased response to the recommended antibiotic, no confirmed cases of complete treatment failure have occurred. Nevertheless, it is important to maintain good public health tracking systems to monitor gonorrhea for signs that it is becoming more resistant to existing antibiotics.

Some Populations Continue to See Higher STI Rates

Once again, young people between the ages of 15 and 24 accounted for almost half of the cases of chlamydia, gonorrhea, and syphilis in 2022. This disproportionate distribution of STIs among young people has remained unchanged since at least 2000. Similarly, 2022 saw a continuation of disproportionate case counts among people belonging to some racial/ethnic groups and sexual orientations. Differences in sexual behavior or risk-taking does not explain why some populations continue to see higher STI rates than others do. Rather, an interaction between inadequate access to comprehensive, confidential sexual health care; socioeconomics; and stigma likely account for a substantial portion the observed disparities.

STI News You May Have Missed

In February 2024, the Department of Health and Human Services released a draft of an addendum to the STI National Strategic Plan that discusses needs and proposes goals necessary to improve prevention and treatment of herpes simplex virus (HSV). The addendum highlights a need for innovation and testing and treatment technologies as well as the need for increased awareness and education. The addendum also discusses the need to decrease the stigma associated with having HSV.

Increasing numbers of gonorrhea infections are not an experience exclusive to the United States. The United Kingdom has also seen an increasing number of gonorrhea cases since the early 2000s. This contributed to the United Kingdom’s Joint Committee on Vaccination and Immunisation advising the use of meningococcal B vaccine to prevent gonorrhea in populations who experience a high rate of infection. Although there is a biological basis for this recommendation and observational evidence that meningococcal B vaccination is associated with a decreased risk of getting gonorrhea, clinical trials have not confirmed the efficacy of using this vaccine to prevent gonorrhea. Several clinical trials evaluating the use of this vaccine to prevent gonorrhea are registered on ClinicalTrials.gov; however, it is difficult to know exactly when to expect published results since many are still recruiting volunteers into the trials.

When it comes to STIs, the goal is often preventing infection in the first place. This is especially true for human immunodeficiency virus (HIV), since it is treatable but not curable. Pre-exposure prophylaxis (PrEP) for HIV has given people an additional tool to prevent HIV infection from sex or intravenous drug use. However, a lawsuit working its way through the Fifth Circuit Appellate Court could change the requirement that health insurance plans must cover evidence-based preventive services without cost-sharing. The lawsuit, Braidwood Management v. Becerra, could make accessing preventative services, including but not limited to PrEP, more expensive for consumers. A simulation study published in January 2024 suggests that even small increases in out-of-pocket costs can significantly increase the number of people who stop taking PrEP, leading to increased HIV diagnoses. The outcome of Braidwood Management v. Becerra could have major impacts on HIV prevention, as well as other preventable health conditions.

Although syphilis and congenital syphilis are notable challenges facing the public health system, they are not the only newsworthy topics in the world of STIs. The 2022 STI statistics are a reminder of the need to remain committed to innovation, treatment, and prevention.