Global seroprevalence of SARS-CoV-2 antibodies: a systematic review and meta-analysis

Abstract

BackgroundStudies reporting estimates of the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies have rapidly emerged. We aimed to synthesize seroprevalence data to better estimate the burden of SARS-CoV-2 infection, identify high-risk groups, and inform public health decision making.MethodsIn this systematic review and meta-analysis, we searched publication databases, preprint servers, and grey literature sources for seroepidemiological study reports, from January 1, 2020 to August 28, 2020. We included studies that reported a sample size, study date, location, and seroprevalence estimate. Estimates were corrected for imperfect test accuracy with Bayesian measurement error models. We conducted meta-analysis to identify demographic differences in the prevalence of SARS-CoV-2 antibodies, and meta-regression to identify study-level factors associated with seroprevalence. We compared region-specific seroprevalence data to confirmed cumulative incidence. PROSPERO: CRD42020183634.FindingsWe identified 338 seroprevalence studies including 2.3 million participants in 50 countries. Seroprevalence was low in the general population (median 3.2%, IQR 1.0-6.4%) and slightly higher in at-risk populations (median 5.4%, IQR 1.5-18.4%). Median seroprevalence varied by WHO Global Burden of Disease region (p < 0.01), from 1.0% in Southeast Asia, East Asia and Oceania to 18.8% in South Asia. National studies had lower seroprevalence estimates than local (p = 0.02) studies. Compared to White persons, Black persons (prevalence ratio [RR] 2.34, 95% CI 1.60-3.43) and Asian persons (RR 1.56, 95% CI 1.22-2.01) were more likely to be seropositive. Seroprevalence was higher among people ages 18-64 compared to 65 and over (RR 1.26, 95% CI 1.04-1.52). Health care workers had a 1.74x (95% CI: 1.18-2.58) higher risk compared to the general population. There was no difference in seroprevalence between sexes. There were 123 studies (36%) at low or moderate risk of bias. Seroprevalence estimates from national studies were median 11.9 (IQR 8.0 - 16.6) times higher than the corresponding SARS-CoV-2 cumulative incidence.InterpretationMost of the population remains susceptible to SARS-CoV-2 infection. Public health measures must be improved to protect disproportionately affected groups, including non-White people and adults. Measures taken in SE Asia, E Asia and Oceania, and Latin America and Caribbean may have been more effective in controlling virus transmission than measures taken in other regions.FundingPublic Health Agency of Canada through the COVID-19 Immunity Task Force.

Seroprevalence of Anti-SARS-CoV-2 Antibodies in a Random Sample of Inhabitants of the Katowice Region, Poland

“…Our findings showed that the frequency of positive IgG results was inversely associated with age. This finding is in line with the conclusion of a recent systematic review that confirmed a larger seroprevalence in people aged 18–64 years compared to the age group 65 years or above [ 4 ]. A Swiss study also showed that young children and older people (≥65 years) had significantly lower seroprevalence than the other age groups [ 6 ].…”

“…The region-wise seroprevalence was 3.17% in Western Europe, 4.41% in Southern Europe, and 5.27% in Northern Europe. Another systematic review and meta-analysis posted in November 2020 reviews the results of 281 serosurveys [ 4 ]. The majority of surveys included in the meta-analysis reported IgG tests (83%) and the review showed a median seroprevalence of 3.2% in the general population worldwide, larger in healthcare workers and caregivers (6.3%).…”

“…In Europe, many seroepidemiological studies have focused on ‘hot-spots’ or ‘high-risk groups’. The published body of evidence regarding the general population provides only a few estimates with the apparent lack of data for Eastern Europe [ 3 , 4 , 8 ]. The apparent difference between our estimates of SARS-CoV-2 seroprevalence and estimates provided by general population studies published in the literature reflects the natural history of the COVID-19 pandemic.…”

Reconciling estimates of global spread and infection fatality rates of COVID‐19: An overview of systematic evaluations

“…Some overarching evaluations have systematically integrated data from multiple studies and countries. [1][2][3][4][5][6] These synthetic efforts probe what are typical estimates of spread and IFR, how heterogeneous they are, and what factors explain heterogeneity. An overview of these systematic evaluations comparing their methods, biases and inferences may help reconcile their findings on these important parameters of the COVID-19 pandemic.…”

Excess deaths associated with the Iranian COVID-19 epidemic: a province-level analysis

“…The only systematic seroprevalence study in Iran took place in Gilan during April 2020 with an estimated prevalence of 21.0% (95%CI: 17.6% - 24.7%) across 528 household and community samples corresponding to an IFR of 0.09% (95%CI: 0.08% - 0.12%) [23]. More recent systematic reviews and meta-analysis of global seroprevalence of SARS-CoV-2 suggests that this seroprevalence study has moderate levels of bias and has overestimated the true prevalence by approximately a factor of 3.9 [24,25]. This implies that the corrected IFR of Gilan is more likely around 0.35% which is much closer to our 0.36% (95%CI: 0.34% - 0.39%) population-weighted IFR estimate.…”