Table 1. Summary characteristics of included articles.
| Characteristic | Studies n (%) |
|---|---|
| Geographic scope | |
| National | 116 (12%) |
| Regional | 347 (36%) |
| Local | 277 (29%) |
| Sublocal | 228 (24%) |
| Age groupsa | |
| Children and Youth (0–17 years) | 28 (3%) |
| Adults (18–64 years) | 268 (28%) |
| Seniors (65+ years) | 7 (0.7%) |
| Multiple age groups | 609 (63%) |
| Population | |
| Studies reporting population-wide estimates | 590 (61%) |
| Studiesreporting population-specific estimatesb | 378 (39%) |
| County income levelc | |
| High income | 747 (77%) |
| Low/middle income | 221 (23%) |
| Sampling method | |
| Probability sampling | 209 (22%) |
| Non-probability sampling | 759 (78%) |
| Antibody testsd | |
| ELISA | 242 (25%) |
| CLIA | 409 (42%) |
| LFIA | 137 (14%) |
| Other | 10 (1%) |
| Neutralization | 4 (0.4%) |
| Multiple types | 37 (4%) |
| Antibody isotypes reportedd | |
| IgG | 845 (87%) |
| IgM | 227 (24%) |
| IgA | 47 (5%) |
| Risk of bias | |
| Low | 28 (3%) |
| Moderate | 443 (46%) |
| High | 424 (44%) |
| Unclear | 73 (8%) |
aWhen the age range for participants in a study overlapped multiple age categories by > = 30% then the study was counted as examining multiple age groups.
bStudies sampling from well-defined population sub-groups.
cClassified according to the WHO global burden of disease region groupings (high vs other—low/middle).
dStudies could have met multiple criteria so the sum of percentages may exceed 100%. Abbreviations: ELISA = enzyme-linked immunosorbent assay; CLIA = chemiluminescence immunoassay; LFIA = lateral flow immunoassay.