In 2016, the HIV prevalence rate in St. Charles County was 99.1 per 100K people, below Missouri’s rate of 237.4. That same year, St. Charles County’s chlamydia rate was 294.6 per 100K people. The gonorrhea and (primary and secondary) syphilis rates were 69 and 2.3.
While O’Fallon’s STD rates are relatively low, health officials worry that they are going up. Since the AIDS scare has abated somewhat with the availability of medicines that suppress the viral load, many people have become lax about using condoms.
Health officials stress that condoms still need to be used, and sexually active people should be tested often. Otherwise, there is no way to know for sure that one is not infected.
There are only a few clinics in O’Fallon, but there are more options in the surrounding areas (and you may have better luck finding free STD testing in St. Louis). You can be tested in the St. Charles County Health Department clinic in nearby St. Charles.
Planned Parenthood is located in St. Peters. They test for STIs and treat all of them except HIV, and the fee is on a sliding scale.