Adapting Serosurveys for the SARS-CoV-2 Vaccine Era

Abstract

Population-level immune surveillance, which includes monitoring exposure and assessing vaccine-induced immunity, is a crucial component of public health decision-making during a pandemic. Serosurveys estimating the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in the population played a key role in characterizing SARS-CoV-2 epidemiology during the early phases of the pandemic. Existing serosurveys provide infrastructure to continue immune surveillance but must be adapted to remain relevant in the SARS-CoV-2 vaccine era. Here, we delineate how SARS-CoV-2 serosurveys should be designed to distinguish infection- and vaccine-induced humoral immune responses to efficiently monitor the evolution of the pandemic. We discuss how serosurvey results can inform vaccine distribution to improve allocation efficiency in countries with scarce vaccine supplies and help assess the need for booster doses in countries with substantial vaccine coverage.

Keywords: 19; 2; COVID; CoV; SARS; cross; sectional; seroprevalence; vaccines.

Figure 1.

Conceptual decision tree for distinguishing between an infection- and vaccine-induced humoral immune response. Serosurvey investigators should collect all data simultaneously (eg, deploy anti-S and anti-N assays together) before applying the conceptual decision tree. Assays measuring total antibodies or IgG can be used. Anti-RBD assays can be used in place of anti-S assays. A past diagnosis, if present, can support the conclusion that an individual should be assigned to group A or C. This decision tree is only applicable for S-targeting vaccines. Abbreviations: IgG, immunoglobulin; N, nucleocapsid protein; RBD, receptor-binding domain; S, spike glycoprotein.