Coinfections with multiple sexually transmitted pathogens in Republic of Korea, 2018–2020

BACKGROUND: Sexually transmitted infections (STIs) can have serious consequences, and the global STI incidence remains high. However, there is little information on the frequency of STIs with multiple pathogens according to age. Accordingly, we conducted a study to determine the trends of coinfection with sexually transmitted pathogens according to age in the Republic of Korea from 2018 to 2020. METHODS: From January 2018 to December 2020, 65,191 samples of swab, urine, and other types submitted for STI screening were obtained from U2Bio Co. Ltd. (Seoul, Republic of Korea). Multiplex polymerase chain reaction, a sensitive and rapid method for simultaneous detection of STIs caused by multiple different pathogens, was performed using an AccuPower STI4C‐Plex Real‐Time PCR kit, AccuPower STI8A‐Plex Real‐Time PCR kit, and AccuPower STI8B‐Plex Real‐Time PCR kit with an Exicycler 96 Real‐Time Quantitative Thermal Block. RESULTS: Of the 65,191 samples tested, 35,366 (54.3%) tested positive for one or more sexually transmitted pathogens. The prevalence of coinfections with two or more sexually transmitted pathogens was inversely proportional to age. Furthermore, the rates of coinfection with sexually transmitted pathogens and age distribution differed according to sex and the sexually transmitted pathogen type. CONCLUSION: This study confirmed that a significant proportion of patients with STIs are coinfected with multiple pathogens. Public health managers could use these results to recognize and prevent STIs according to age.