The declining trend in HIV prevalence from population-based surveys in Cameroon between 2004 and 2018: myth or reality in the universal test and treat era?

BACKGROUND: HIV remains an epidemic of major public health importance in Cameroon but a decline in HIV prevalence has been observed according to population-based surveys conducted in 2004, 2011 and 2018. We sought to review current evidence for declining HIV prevalence despite increasing survival owing to ‘universal test and treat’ and to explore the reason for the decrease, particularly the role of behavioural change. METHODS: We conducted a secondary analysis using HIV prevalence, behavioural and social determinants data of the Demographic and Health Survey Program databases. Trend lines were fitted to data that were available for a minimum of three points in time during the 1991–2018 period. Regression coefficients associated p-values and 95% confidence intervals were obtained using Microsoft Excel software. RESULTS: Overall adult HIV prevalence decreased significantly from 5.4% (95%CI: 4.8-6.0) in 2004 to 4.3% (95%CI: 3.8–4.8) in 2011 and further down to 2.7% (95%CI: 2.3–3.1) in 2018 at a rate of about 1.4% every septennium (β = -1.4, R² = 0.98, p = 0.03). Yet, the number of persons surviving with HIV increased from about 0.05 million in 1991 to 0.5 million in 2018 corresponding to an increase in access to antiretroviral therapy from less than 10% to universal coverage of 80% respectively. Concurrent reductions in risky sexual behaviours were observed: a delayed sexual debut by one year, decreased sexual violence by 7%, decreased polygamous unions by 16%, decreased multiple sexual partners by 15.3% and increased condom use by 26.3%. CONCLUSION: The observed decline in HIV prevalence is statistically valid and reflects the observed decline in risky sexual behaviour that need to be sustained by the National HIV programme. Though universal access to ART has increased the number of persons surviving with HIV, this has not led to an increased prevalence of HIV in a setting with a rising population.