Table 1. Seroprevalence of antibodies to SARS-Cov-2 in blood donors, estimates adjusted for specificity and sensitivity. Rio de Janeiro, Brazil, April 14-27, 2020.

Estimates	Sample size	Prevalence (%)	95%CI
Unadjusted	2,857	4.0	3.3–4.7
Weighted* for Rio de Janeiro population	2,857	3.8	3.1–4.5
Adjusted for sensitivity and specificity	2,857	3.6	2.7–4.4
Weighted* estimate adjusted for sensitivity and specificity	2,857	3.3	2.6–4.1

* Weighted according to the population of Rio de Janeiro aged 18-69 years, by age and gender.