Eligibility criteria
We included the publications that reported primary data related to HSV-2 for any of the four outcomes (1) seroprevalence, which was defined by the proportion of the included population who tested HSV-2 seropositive; (2) seroincidence or seroconversion, defined as the occurrence of HSV-2 infections per person-time; (3) the proportion of genital ulcer disease (GUD) cases in which HSV-2 was isolated as its cause; (4) the proportion of genital herpes cases in which HSV-2 was isolated as its cause.
We excluded case reports, case series, commentaries, reviews, and publications without access to the full text. We also excluded the studies that involved less than 10 participants. Those studies reporting HSV-related outcomes (including both HSV-1 and HSV-2) were excluded if we could not extract HSV-2 outcomes. If one study only reported HSV-2 prevalence from infants younger than six months, we excluded it due to the parental source antibody.20