Impact of COVID-19 on STDs

Sexually Transmitted Disease Surveillance, 2020 serves as a stark reminder that STDs continue to persist as a significant public health concern, even in the face of a pandemic. The new report reflects the realities of a strained public health infrastructure, while simultaneously providing the most current data on reported cases of STDs in the United States. However, the picture remains very unclear. Coronavirus disease 2019 (COVID-19) significantly affected trends in STDs during 2020 – resulting in likely underreporting of infections and possibly increased STD transmission. It’s likely that such effects will persist for several more years and we may never know the full impact of the pandemic on STDs. What is clear, however, is the state of STDs did not improve in the United States. Prevention and control efforts remain as important as ever.

Below we describe the effect of COVID-19 on STD surveillance activities and data collected in 2020 in more detail and ask that you consider this information as you explore the rest of the report.

Impact on STD Case Surveillance   

Before preventive measures to reduce the spread of COVID-19 were put in place in the United States, the weekly number of diagnosed and reported chlamydia, gonorrhea, and primary and secondary (P&S) syphilis case counts were all higher in 2020 compared to 2019. Unsurprisingly, the number of reported STDs rapidly fell during initial shelter-in-place orders in March and April 2020.

Factors contributing to the initial decrease in STD case counts included:

  • Reduced screening: Many healthcare clinics either closed entirely or limited in-person visits to symptomatic patients only. STDs often do not show symptoms, and screening is necessary for timely diagnosis and treatment. Additionally, decreased routine healthcare visits, increased unemployment and loss of health insurance, as well as STD test kit and laboratory supply shortages, may have reduced screening during the pandemic.
  • Limited resources: STD program resources shifted to help control the spread of COVID-19. Many jurisdictions redirected staff from routine STD surveillance and control efforts to COVID-19 activities. The observed drop in reported STD cases may reflect challenges in maintaining key STD activities, including case investigation, partner services, and case reporting.
  • Social distancing measures: Because COVID-19 can spread during sexual contact, social distancing measures (e.g., shelter-in-place orders) were used to mitigate disease. These measures may have influenced sexual behaviors by limiting sexual activity or the number of new sexual partners, thus reducing the spread of STDs. The fear of being exposed to COVID-19 and limited access to public transportation also may have affected sexual behaviors and led to people with STD symptoms delaying care.

Although initial decreases were observed across STDs, deficits were more pronounced for chlamydia. Trends later in the year showed continued decreases in chlamydia cases, while reported cases of gonorrhea and P&S syphilis increased. These data reflect the complicated effect of COVID-19 on STD trends.

Reductions in Chlamydia Diagnoses

By the end of 2020, the number of reported cases of chlamydia decreased by nearly 13%. However, this decrease is likely due to changes in STD screening, not a reduction in new infections. Most people with chlamydia usually have no signs or symptoms and most cases are identified through screening at routine preventive care visits. Therefore, it is likely chlamydia was disproportionately affected by reduced screening during the pandemic, resulting in undiagnosed infections. Additionally, in response to reduced staffing resources, many health departments prioritized the diagnosis and treatment of syphilis and gonorrhea. This likely further reduced the number of chlamydia cases processed and reported.

Area graph showing weekly chlamydia case counts in 2020 relative to the same week in 2019.
Chlamydia — Reported 2020 Cases as a Percentage of 2019 by MMWR Week, United States
Area graph showing weekly gonorrhea case counts in 2020 relative to the same week in 2019.
Gonorrhea — Reported 2020 Cases as a Percentage of 2019 by MMWR Week, United States
Area graph showing weekly primary and secondary case counts in 2020 relative to the same week in 2019.
Primary and Secondary Syphilis — Reported 2020 Cases as a Percentage of 2019 by MMWR Week, United States

Increases in Gonorrhea and Syphilis, including Congenital Syphilis 

Although case counts for gonorrhea and P&S syphilis dropped below 2019 levels during March and April 2020, cases of both STDs surged the rest of the year. By the end of 2020, reported cases of gonorrhea increased 10% and reported cases of P&S syphilis increased 7% from 2019 to 2020.

Increased case counts seen in late-2020 may reflect an increase in service utilization as health care clinics re-opened.  It is also possible more people sought care when available for P&S syphilis, since symptoms can be visible, and gonorrhea symptoms can be painful, particularly in men. Furthermore, clinics may have continued targeting services to patients most likely to be infected, increasing the number of cases identified.

Increases in case reporting could also reflect higher disease transmission during 2020. For example, due to reduced access to care, those with an STD may have had their infections longer, providing more opportunities to transmit infection to their sexual partners. Additionally, following the initial shelter-in-place orders, sexual behaviors may have changed, including frequency of new sexual partners, leading to spread in sexual networks.

Concerningly, rates of P&S syphilis increased 24% among reproductive-aged women from 2019 to 2020, resulting in increases in congenital syphilis. In 2020, there were 2,148 congenital syphilis cases, an increase of 15% since 2019. Increases in congenital syphilis, including increases in congenital syphilis-related deaths, are a stark reminder of the need to prevent the worst outcomes related to STDs.

Impact on Enhanced and Sentinel STD Surveillance  

The COVID-19 pandemic also affected enhanced and sentinel surveillance activities in 2020.

STD Surveillance Network (SSuN)

Jurisdictions participating in SSuN conduct both:

  • sentinel surveillance in STD clinics to monitor trends in patient demographics, provision of STD-related health services, and the proportion of patients testing positive for an STD; and
  • enhanced gonorrhea surveillance by completing patient and provider follow-up on a representative sample of reported cases.

COVID-19 significantly disrupted in-person STD health services in SSuN jurisdictions (e.g., clinic closures, prioritizing symptomatic patients), reducing the number of patient visits. Given these changes in service provision, the proportion of clinic patients testing positive for STDs in 2020 is higher than in previous years which may reflect targeted testing among patients most likely to have an infection.

Enhanced surveillance helps describe the epidemiology of gonorrhea, including trends by sex and sex of sex partners and in the proportion of cases receiving appropriate treatment. During the pandemic, several jurisdictions either suspended enhanced investigations or completed fewer enhanced investigations due to staffing resources. As a result, some jurisdictions did not have sufficient SSuN data to include in this report.

Gonococcal Isolate Surveillance Project (GISP)

Jurisdictions participating in GISP conduct sentinel surveillance for drug resistant gonorrhea by collecting specimens from symptomatic men diagnosed with urogenital gonorrhea at STD clinics. Regional laboratories conduct antimicrobial susceptibility testing, and results are used to inform treatment guidelines. Like STD clinics participating in SSuN, many clinics collecting Neisseria gonorrhoeae isolates as part of GISP experienced temporary closures or prioritized other clinic services. Although some clinics were able to conduct GISP activities throughout 2020, many clinics were only able to collect isolates for part of the year, with an average clinic participation of 9 months. As a result, there was a 32% decrease in the number of gonococcal isolates collected in GISP compared to 2019. Therefore, the GISP data presented in this report should be viewed with some caution. Although the number of isolates was reduced in 2020, GISP data presented in this report continue to reflect similar trends demonstrated in prior years.  


The COVID-19 pandemic has introduced uncertainty and difficulty in interpreting STD surveillance data collected during 2020. Trends presented in Sexually Transmitted Disease Surveillance, 2020 should be interpreted cautiously. As the pandemic continues, the ability to obtain an accurate picture of the STD epidemic in the U.S. may be impaired beyond 2020. Additionally, the impact of delayed STD diagnoses and treatment on adverse outcomes, such as pelvic inflammatory disease and infertility, remain to be seen. However, one thing is clear – STD cases are still too high. Adequate public health resources are needed now more than ever. We must prioritize on-the ground support for STD prevention and surveillance programs through disease investigation, contact tracing, training, partnerships, and community engagement.


This page summarizes a number of publications and communications throughout the pandemic. You can find more information in the following resources:  

Additional COVID-19 information is available here: