Sexually Transmitted Disease Surveillance, 2020 serves as a reminder that STDs remain a significant public health concern, even in the face of a pandemic. In 2020, COVID-19 significantly affected STD surveillance and prevention efforts. This 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. Trends presented in this report should be interpreted cautiously. 


In 2020, a total of 1,579,885 cases of Chlamydia trachomatis infection were reported to the CDC, making it the most common notifiable sexually transmitted infection in the United States for that year. This case count corresponds to a rate of 481.3 cases per 100,000 population, a decrease of 13% compared with the rate in 2019. During 2019–2020, rates of reported chlamydia decreased among both males and females, in all regions of the United States, and, except for rates among non-Hispanic persons of multiple races, among all racial/Hispanic ethnicity groups.

Decreases in rates of reported chlamydia in 2020 are unlikely due to a reduction in new infections. As chlamydial infections are usually asymptomatic, case rates are heavily influenced by screening coverage. During the COVID-19 pandemic, many health care clinics limited in-person visits to patients with symptoms or closed entirely, and it is likely that preventive health care visits where STD screening usually happens, such as annual reproductive health visits for young women, decreased. During the initial shelter-in-place orders in March and April of 2020, the number of chlamydia cases decreased substantially when compared to the number of cases reported in 2019 and the deficit persisted throughout the year.

Rates of reported chlamydia are highest among adolescents and young adults. In 2020, almost two-thirds (61%) of all reported chlamydia cases were among persons aged 15–24 years. Decreases in rates of diagnosed and reported chlamydia during 2020 were most noticeable among females aged 15–24 years, one of the populations targeted for chlamydia screening. Although still high, rates of reported chlamydia decreased 15% among 15–19-year-old females and decreased 10% among 20–24-year-old females during 2019–2020.