The Centers for Disease Control and Prevention’s (CDC) 2021 STD Surveillance Report indicates cases of sexually transmitted diseases decreased during the early months of the pandemic, but most resurged by the end of the year and into 2021.
The CDC report also highlighted how STD rates (number of infections per 100,000 people) vary by state, age, and sex. Here's a deeper look at that data.
STDs, or sexually transmitted diseases, are infections that are primarily spread through sexual contact. These diseases affect both men and women and are caused by bacteria, viruses, parasites, or other microorganisms. STDs can be transmitted through vaginal, anal, or oral sex, or from mother to child during childbirth or breastfeeding.
STDs are also commonly referred to as STIs (sexually transmitted infections).
The CDC tracks reported cases of chlamydia, gonorrhea, syphilis, and congenital syphilis.
Human papillomavirus, or HPV, is the most common STD in the nation, but most people with the infection have no symptoms, and no national case-reporting system for HPV infections exists.
Of the STDs tracked by the CDC, chlamydia makes up the largest proportion of cases in the US, with over 1.6 million cases (496 cases per 100,000 people) reported to the CDC in 2021.
It's also worth noting that HIV data is collected in a separate CDC Surveillance Report. There were 36,136 cases reported in 2021.
In 2021, the five states with the highest combined rates of chlamydia, gonorrhea, and syphilis cases per 100,000 people were Mississippi, Louisiana, Alaska, South Carolina, and South Dakota.
|STD cases per 100,000 people
Younger adults are more likely to be affected by STDs, but differences in infection rates between men and women vary by type of STD.
Women were more likely than men to report chlamydia infections. However, men were more likely to report both gonorrhea and syphilis infections.
Infection rates peaked between the ages of 20–34, and nearly half (46%) of all new STDs occur among people between the ages of 15–24. Adults over 35 were less likely than younger adults to report chlamydia, gonorrhea, and syphilis infections.