Seroprevalence of SARS-CoV-2 antibodies in Ethiopia: findings from the 2022 national population-based survey (second round)

Among 14,074 participants (99% response rate; 58.9% female; mean age 35.3 years), the overall national seropositivity for SARS-CoV-2 antibodies was 48.0% (95% CI: 46.6-49.4%). IgG seroprevalence (45.1%) significantly exceeded IgM (1.2%), indicating predominantly past infections. Significant geographic variation existed, with Addis Ababa showing the highest seropositivity (68.1%; 95% CI: 65.7-70.5%) and Sidama (39.6%; 95% CI: 36.39-42.98%) and Gambella (40.5%; 95% CI: 37.01-44.02%) the lowest. Higher seropositivity was observed in females (50.1% vs. males 45.8%), urban residents (55.6% vs. rural 45.7%), and vaccinated individuals (59.1% vs. unvaccinated 37.2%). Multivariate analysis identified key predictors: vaccinated individuals had 2.64-fold higher odds (AOR = 2.64: 95% CI = 2.34-2.99; p < 0.001); urban residence increased odds by 41% (AOR = 1.41; 95% CI = 1.25-1.59; p < 0.001); diabetes (AOR = 1.87; 95% CI = 1.17-2.97; p = 0.009) and hypertension (AOR = 1.72; 95% CI = 1.23-2.41; p = 0.001) elevated risk; while smoking reduced odds by 24% (AOR = 0.76; 95% CI = 0.60-0.97; p = 0.028). Older age groups showed progressively higher odds (e.g., 55-64 years: AOR = 1.56; 95% CI = 1.19-2.06; p < 0.001 vs. 15-24 years) CONCLUSION: The study found Nearly half of Ethiopians had SARS-CoV-2 antibodies by mid-2022, with Significant disparities by regions, demographic groups, and vaccination status. Dominance of IgG antibodies (45.1%) over IgM (1.2%) indicates widespread prior infection. An identified rural immunity gap underscores the urgent need for targeted vaccination strategies among high-risk subgroups in underserved areas to advance toward herd immunity.