Prevalence of chlamydia and gonorrhoea among Kenyan adolescents

Sexually transmitted infections (STIs) diagnoses in Kenya are based on the identification of characteristic symptoms or syndromes without laboratory testing. Syndromic management likely underestimates STI prevalence due to undiagnosed asymptomatic infection. We assessed the prevalence and factors associated with chlamydia and gonorrhoea infections among adolescent boys and girls participating in Maneno Yetu, a sexual and reproductive health study in Kenya.

Adolescents aged 15-19 years residing in informal settlements in Kisumu were eligible to participate in a cross-sectional survey. Participants were recruited using respondent-driven sampling. Urine specimens were tested using the Molecular Xpert CT/NG test. Associations were assessed by multivariate logistic regression.

STI testing was offered to 1238 adolescents who reported having sex and 1167 accepted. Of the 1159 adolescents who had interpretable STI test results, 53% were girls and 74% were 18-19 years old. STI prevalence was 9.6% overall and higher among girls than boys (12.5% vs 6.3%; p<0.001). Of 111 adolescents who tested positive, 96 had chlamydia, 9 had gonorrhoea, 6 had both chlamydia and gonorrhoea, and 73 reported never experiencing any STI symptoms. Girls were twice more likely than boys to test positive for an STI after controlling for other demographic characteristics, sexual behaviour and STI-related characteristics (aOR=2.01, 95% CI 1.25, 3.24).

Nearly 10% of adolescents were diagnosed with chlamydia or gonorrhoea. STI prevalence was two times higher among girls than boys. Two-thirds of adolescents with a positive STI test result did not report experiencing symptoms and thus would have been missed by syndromic management. Undiagnosed and untreated STIs can result in onward transmission and significantly impact their reproductive health. Our findings lend support for expanding STI testing services in resource-constrained settings and developing point-of-care diagnostic assays that are rapid, inexpensive and accurate to address the STI epidemic and reduce the risk of sequelae.