In-hospital mortality among children and adults hospitalized with COVID-19 in Africa across pre-delta, delta, and omicron SARS-CoV-2 waves

Int J Infect Dis. 2025 Aug:157:107924. doi: 10.1016/j.ijid.2025.107924. Epub 2025 May 8.

Abstract

Background: This study examines in-hospital mortality among children and adults hospitalized with COVID-19 across the pre-Delta, Delta, and Omicron waves in the African region.

Method: We conducted a retrospective cohort study using individual-level data from 520,810 hospitalized children and adults in 13 African countries. Cox proportional hazards regression models were used to assess the impact of SARS-CoV-2 variants on in-hospital mortality.

Findings: Among children, the risk of in-hospital mortality was comparable between pre-Delta and Delta waves (aHR 1.02, 95% CI 0.77-1.35). In adults, mortality increased by 6% during Delta wave compared with pre-Delta wave (aHR 1.06, 95% CI 1.04-1.09). During Omicron wave, mortality risk decreased significantly by 42% in children (aHR 0.58, 95% CI 0.43-0.80) and 59% in adults (aHR 0.41, 95% CI 0.40-0.43) compared to the Delta wave. Notably, the reduction in mortality risk during the Omicron wave was less pronounced for children with severe or critical COVID-19, those co-infected with HIV, and adults co-infected with either HIV or tuberculosis.

Conclusion: Despite a general reduction in mortality risk during Omicron wave, persistently high mortality in specific high-risk groups underscores the importance of prioritizing booster vaccinations and intensified treatment for vulnerable populations as per WHO recommendations.

Keywords: African region; COVID-19; Children and adults; SARS-CoV-2 variants.

MeSH terms

  • Adolescent
  • Adult
  • Africa / epidemiology
  • Aged
  • COVID-19* / epidemiology
  • COVID-19* / mortality
  • COVID-19* / virology
  • Child
  • Child, Preschool
  • Female
  • Hospital Mortality*
  • Hospitalization / statistics & numerical data
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Retrospective Studies
  • SARS-CoV-2*
  • Young Adult

Supplementary concepts

  • SARS-CoV-2 variants