Reported cases of sexually transmitted diseases hit an all-time high in 2015, according to a new report from the U.S. Centers for Disease Control and Prevention, which tracks the three most common STDs: chlamydia, gonorrhea and syphilis. The CDC attributes the upswing to an erosion of public prevention resources and treatment services, as well as increased screening. An increase in online dating may also contribute, especially for young men who have sex with men, says Eric Schrimshaw, a professor at the Columbia University Mailman School of Public Health. Schrimshaw thinks more extensive and comprehensive sex education, along with better community services, could most effectively overturn the trend. At their worst, STDs can cause infertility, cancer and death—and their spread can lead to antibiotic resistance.

By the Numbers

110 million

Estimated total number of STD infections in the U.S.

478.8

Chlamydia cases per 100,000 people

5.9%

Increase in chlamydia cases from 2014 to 2015—an all-time high

12.8%

Rate increase in gonorrhea

19%

Rate increase in syphilis

$16 billion

Annual cost of treating STDs

Source: Sexually Transmitted Disease Surveillance 2015. U.S. Centers For Disease Control And Prevention, October 2016