Rates of sexually transmitted infections are going to "skyrocket" — a ripple effect of the COVID-19 pandemic and an indictment of the chronic underfunding of public health services, the researcher behind a new study said.

Over 27,000 chlamydia cases and 5,500 gonorrhea cases went undetected in less than four months after March 13, 2020, according to a study published May 19 in the American Journal of Preventive Medicine. 

"This is going to surge," said Casey Pinto, the lead author of the study and an assistant professor in Pennsylvania State University's department of public health sciences. The data showed routine STI testing plummeted as clinics across the nation shut down or drastically reduced services; the testing nadir was in early April, when people received less than half of the expected tests.

"People not getting tested are still having sex, and they're still spreading this," Pinto said. "What we will end up seeing is higher rates of STIs." 

In a few years, Pinto said, she also expects to see slightly higher rates of infertility, which can result from untreated STIs. About 80% of cases of chlamydia and gonorrhea in women are asymptomatic, which is partly why routine screening is recommended. Untreated STIs can increase the risk of HIV infection, pelvic inflammatory disease and adverse pregnancy outcomes, including life-threatening ectopic pregnancy.

For the study, Pinto and her co-authors worked with Quest Diagnostics, which provides lab services to much of the U.S. From January 2019 through February 2020, Quest caught about 18% of the total positive chlamydia and gonorrhea cases reported by the Centers for Disease Control and Prevention. Because the 33,000 missed STI cases between March and June were drawn from only Quest's numbers, the researchers estimated that more than 150,000 chlamydia and gonorrhea cases were likely missed nationally, just in those four months.

Within the next year, "You are going to see skyrocketing rates," Pinto said. 

Pinto and her colleagues calculated the testing rates and positivity rates for people ages 14 to 49 from January 2019 through June 2020 based on 18.6 million tests and then compared the weekly averages in the pandemic months of March, April, May and June 2020 with the weekly averages from the pre-pandemic months. They did not calculate a baseline using data from before 2019, because they wanted a conservative estimate of how far testing rates had dropped. 

"Year over year, we're breaking records for STDs, so we felt that if we went back any further than one year, it would skew the numbers and make it look like an even higher drop," Pinto said.

Expected tests fell off soon after the U.S. declared a national emergency on March 13, 2020. 

Before March 2020, the researchers found that Quest Diagnostics was running 131,114 chlamydia tests and 130,831 gonorrhea tests each week. On average, about 6,195 cases of chlamydia and 1,819 cases of gonorrhea were caught each week, meaning average positivity rates were 4.7% and 1.4%, respectively. 

Starting in March, the number of tests went down while the positivity rate went up — but the actual number of positive cases went down. At their pandemic peak in April, there were 3,381 positive chlamydia cases and 1,356 positive gonorrhea cases, significantly fewer cases than expected, but they led to a positivity rate of 5.9% for chlamydia and 2.4% for gonorrhea because of the smaller number of overall tests.

By the last week of June, testing rates were still at only 85% of pre-pandemic levels, and positivity rates were still markedly higher, likely indicating that people were disproportionately getting tested for symptomatic cases, while asymptomatic cases slipped through the cracks.

This evidence of thwarted health care shows the staggering inadequacy of our current health system, Pinto said. 

"Our contact tracers went from contact tracing [for STDs] to training everyone — while doing contact tracing, while their STD cases piled up," she said. "What's happened over the past decade is that public health spending has been slashed, especially for STD programs. … A pandemic hit, all of our STD workers were pulled to do pandemic work, and now you're going to see the repercussions of that."

Political funding priorities undermined the health of Americans, Pinto said. "If we had more money, this shutdown wouldn't have impacted us nearly as much."

The paper, "Impact of the COVID-19 pandemic on chlamydia and gonorrhea screening in the U.S.," published May 19 in the American Journal of Preventive Medicine, was authored by Casey N. Pinto and Guangqing Chi, Pennsylvania State University; Justin K. Niles, Harvey W. Kaufman, Elizabeth M. Marlowe and Damian P. Alagia, Quest Diagnostics; and Barbara Van Der Pol, University of Alabama at Birmingham.