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Table 2 SARS-CoV-2 anti-RBD total antibody seroprevalence in blood donors by participant characteristics and location

From: SARS-CoV-2 exposure in Malawian blood donors: an analysis of seroprevalence and variant dynamics between January 2020 and July 2021

Variable Category Sample size Seropositive (frequency) Unadjusted (%) Estimate SE z value p value
Intercept      − 6.12 0.76 − 8.11 < 0.001
Gender Female 1393 407 29.2% Ref Ref Ref Ref
Male 3692 994 26.9% 0.05 0.09 0.58 0.56
Age group 15–19§ 912 265 29.1% Ref Ref Ref Ref
20–29 2465 684 27.7% − 0.04 0.11 − 0.32 0.75
30–39 1068 284 26.6% − 0.01 0.13 − 0.06 0.95
40–49 596 154 25.8% 0.16 0.15 1.04 0.3
50+ 44 14 31.8% 0.2 0.38 0.53 0.6
Location Balakaφ 1198 254 21.2% Ref Ref Ref Ref
Blantyre 1351 416 30.8% 0.77 0.13 5.92 < 0.001*
Lilongwe 1328 345 26.0% 0.6 0.13 4.56 < 0.001*
Mzuzu 1208 386 32.0% 0.86 0.13 6.41 < 0.001*
  1. This is an unweighted multivariable logistic regression model with sex, age group, location, and time as predictors
  2. §Recruitment limited to blood donors ≥15 years of age
  3. *Significant based on p value < 0.05
  4. φBalaka was used as a reference as it is the only Malawi Blood Transfusion Service (MBTS) static site that directly covers the rural area