Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Flowchart showing recruitment and participant selection. The blood specimens were collected at multiple time points following vaccination. The second dose of the vaccine was of the same vaccine type (homologous). n indicates number and * Denotes participants who didn’t report previous infection in the survey but gave positive IgG titer indicating previous undiagnosed SARS-COV-2 infection.
