Seroprevalence of Antibodies Specific to Receptor Binding Domain of SARS-CoV-2 and Vaccination Coverage Among Adults in Los Angeles County, April 2021: The LA Pandemic Surveillance Cohort Study


Understanding the presence of adaptive immune responses that are associated with protection from disease (potential protective immunity) caused by SARS-CoV-2 at the population level is critical for public policy. Potential protective immunity can be acquired either through vaccination or past infection.13 We used history of vaccination or presence of antibodies specific to the receptor binding domain (RBD antibodies) of the spike protein of the SARS-CoV-2 virus as potential markers for potential protective immunity as both are strongly associated with presence of neutralizing antibodies.4,5 We conducted surveys and serologic tests in a representative community sample to estimate the fraction of the Los Angeles County (LAC) adult population that had potential protective immunity in April 2021. We tested for differences in potential protective immunity by demographics and whether presence of RBD antibodies waned with time since infection.

A press release about this study can be found here. The full study is available at JAMA Network Open.