Abstract
Delayed Seasonality but Consistent Age Burden: RSV Epidemiology Pre-, During, and Post-COVID-19 Pandemic on the Kenyan Coast (2008-2026)
Katama, E. N.
Maina, G.
Mutunga, M.
Lewa, C.
Cheruiyot, R.
Kea, A.
Shebe, M.
Nyiro, J. U.
Sande, C. J.
Agoti, C. N.
Open Forum Infect Dis. 2026; 13ofag600
Permanent descriptor
https://doi.org/10.1093/ofid/ofag600BACKGROUND: The COVID-19 pandemic and associated nonpharmaceutical interventions disrupted the established epidemiological patterns of many endemic respiratory viruses globally. However, its impact on respiratory syncytial virus (RSV) epidemiology in sub-Saharan Africa is understudied. METHODS: We analyzed data from a continuous hospital-based pediatric pneumonia surveillance program in coastal Kenya January 2008-June 2026. Children ≤5 years, admitted with World Health Organization-defined syndromic severe or very severe pneumonia were tested for RSV using quantitative reverse transcriptase polymerase chain reaction. The period was stratified into prepandemic (January 2008-March 2020), during pandemic (March 2020-May 2023), and postpandemic (May 2023-June 2026). Multivariable logistic regression evaluated clinical and demographic shifts across periods. RESULTS: Among 10 374 tested children, 2442 (23.5%) were RSV positive. Positivity declined from 25.3% (1919/7585) prepandemic to 18.3% (235/1282) during the pandemic and 19.1% (288/1507) postpandemic. Overall median age of RSV-positive patients remained statistically consistent across all periods (4.3 vs 3.7 vs 3.1 months; P = .108), with ≤6-month-olds accounting for ∼62% of admissions throughout. However, in the 2020-2021 season, RSV-positive children had increased median age (6.7; interquartile range: 2.0-15.1 months). In multivariable analysis, fever was less frequent during and postpandemic (adjusted P < .001), and cough decreased postpandemic (adjusted P = .002). Pneumonia severity and overall mortality did not significantly differ across the periods. Local RSV season onsets exhibited 1-2 months' delay during and postpandemic compared to prepandemic. CONCLUSIONS: Despite a repeated 1- to 2-month delay of RSV season onsets on the Kenyan coast and minor clinical symptoms shifts, the core demographic patterns remained stable. The persisting severe RSV disease in <6-month-olds highlights this population for RSV interventions.