This week PLOS Medicine launches the research content in our Collection on Prevention, Diagnosis, and Treatment of Sexually Transmitted Infections (STIs), advised by Guest Editors Nicola Low of the University of Bern, Switzerland and Nathalie Broutet of the World Health Organization (WHO).

More than 1 million people acquire an STI each day. These infections, when not treated, take their toll in grievous outcomes--notably cancer deaths, infertility, and birth complications including stillbirth. Social stigma that limits care-seeking, causal pathogens with diverse characteristics, and commonly mild or nonexistent symptoms all contribute to the pernicious effects of STIs.

Four Research Articles will be published in the Collection in December, addressing diverse topics in the field. In the first study, Christine Johnston of the University of Washington in Seattle and colleagues use cross-sectional data to examine the prevalence of dual-strain HSV-2 infection. This measure of immune system efficacy can signal potential for vaccine development. Next, Emma Wilson of the London School of Hygiene & Tropical Medicine and colleagues report on their trial assessing the impact of an online STI testing service on uptake and diagnosis. Further, in a qualitative thematic analysis, Kipruto C. Chesang of Centers for Disease Control and Prevention in Nairobi and colleagues present a thematic analysis of interviews with Kenyan STI health care providers (HCPs), providing the HCP perspective on programming, training, and stigma in STI care in that setting. Finally, the Collection touches on the global issue of market availability of low-cost antibiotics for STIs. Using country-level surveys and stakeholder interviews, Stephen Nurse-Findlay of the World Health Organization and colleagues investigate the global frequency of benzathine penicillin shortages and uncover commonly noted causes.

Guest Editors Nicola Low of the University of Bern, Switzerland, and Nathalie Broutet of the WHO have authored December's PLOS Medicine Editorial, which highlights key advances from the month's Collection papers and discusses prominent challenges and priorities in the field. The Collection will continue with further research and discussion articles appearing over the next few weeks.