Gonorrhoea, chlamydia and trichomoniasis are common curable sexually transmitted infections (STIs) caused by the bacteria Neisseria gonorrhoeae. Estimates of prevalence and incidence of STIs are important for monitoring STI treatment and prevention programmes and for advocating for funding for STI programming and for the development of new treatments and prevention tools. For gonorrhoea, this is particularly important given the emergence of N. gonorrhoeae resistance to the few remaining antimicrobials recommended for treatment.

Estimated number of individuals 15 to 49 years of age who have an STI

Sex: male, female

STI: gonorrhoea, chlamydia, trichomoniasis

Countries were grouped into 10 geographical regions (similar to SDG regions). For all regions, apart from North America, estimates were generated using a Bayesian meta-analytic approach to produce pooled prevalence estimates for women and men based on prevalence data. Study inclusion criteria included: sample size of at least 100, specimens collected from 2013 through 2020, internationally recognized diagnostic test with adequate performance characteristic on urine, urethral or cervicovaginal specimens was used, and the population studied could be considered representative of the general population. Data from studies that met the inclusion criteria were standardized by applying adjustment factors for the laboratory diagnostic test and study location (rural versus urban) and the age of the study population. Estimates for North America were based on national estimates produced by the United States Centers for Disease Control and Prevention. Estimates for the 10 regions were then translated into global and WHO regional estimates using UN population estimates of the number of women and men aged 15-49 years of age.

Incidence estimates in men and women were based on regional prevalence estimates for the 10 geographical regions used in the prevalence calculations. Incidence estimates for all regions, apart from North America, were calculated for women and men using the equation: incidence = prevalence/average duration of infection. The average duration of infection in each estimation region was assumed to depend on the average duration of infection in the absence of treatment for symptomatic and asymptomatic individuals and the probability that symptomatic and asymptomatic individuals are treated appropriately. The same duration parameter values were used in 2016 and 2020. Estimates for North America were based on national estimates produced by the United States Centers for Disease Control and Prevention. Estimates for the 10 regions were then translated into global and WHO regional estimates using UN population estimates of the number of women and men aged 15-49 years of age.

Every 4 to 5 years

jrowley@who.int

Jane Rowley

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