Forecasting the effect of HIV-targeted interventions on the age distribution of people living with HIV: a case study from Kenya.

OBJECTIVES: Expansion of ART and increases to life expectancy have led to aging among people living with HIV (PWH).

DESIGN: Kenyan decisionmakers need accurate forecasts of the age distribution of PWH to inform future policies.

METHODS: We developed a model of HIV in Kenya, calibrated to historical estimates of HIV epidemiology. We forecasted changes in population size and age distribution of new HIV infections and PWH under the status quo and under scale-up of HIV services.

RESULTS: Without scale-up, new HIV infections were forecasted to fall from 34,000 [28,000-41,000] in 2025 to 29,000 [15,000-57,000] in 2040; the percent of new infections occurring among persons over 30 increased from 33% [20-50%] to 40% [24-62%]. The median age of PWH increased from 39 years [38-40] in 2025 to 43 years [39-46] in 2040, and the percent of PWH over age 50 increased from 26% [23-29%] to 34% [26-43%]. Under the full intervention scenario, new infections were forecasted to fall to 6,000 [3,000-12,000] in 2040. The percent of new infections occurring in people over age 30 increased to 52% [34-71%] in 2040, and there was an additional shift in the age structure of PWH (forecasted median age of 46 [43-48] and 40% [33-47%] over age 50).

CONCLUSIONS: PWH in Kenya are forecasted to age over the next 15 years; improvements to the HIV care continuum are expected to contribute to the growing proportion of older PWH.