Key facts More than 1 million sexually transmitted infections (STIs) are acquired every day worldwide. Each year, there are an estimated 357 million new infections with 1 of 4 STIs: chlamydia, gonorrhea, syphilis, and trichomoniasis. More than 500 million people are estimated to have genital infection with herpes simplex virus (HSV). More than 290 million women have human papillomavirus (HPV) infection (1). The majority of STIs have no symptoms or only mild symptoms that may not be recognized as an STI. STIs such as HSV type 2 and syphilis can increase the risk of HIV acquisition. 988 000 pregnant women were infected with syphilis in 2016, resulting in over 200 000 stillbirths and newborn deaths. In some cases, STIs can have serious reproductive health consequences beyond the immediate impact of the infection itself (e.g., infertility or mother-to-child transmission) Drug resistance, especially for gonorrhea, is a major threat to reducing the impact of STIs worldwi...