The incidence of chlamydia, gonorrhea and syphilis is increasing, according to a new report from the Centers for Disease Control and Prevention. An estimated 110 million Americans now are infected with a sexually transmitted disease.
Chlamydia is the most common S.T.D., and the number of cases rose 4.7 percent from 2015 to 2016. The increases occurred nationwide; rates were highest in the South and lowest in the Northeast.
Chlamydia is usually asymptomatic, and the number of reported cases may have grown in part because of newer, more sensitive screening techniques.