The Kinetics of COVID-19 Vaccine Response in a Community-Vaccinated Population
Michael K. Tu, Samantha H. Chiang, Richard A. Bender, David T. W. Wong and Charles M. Strom
J Immunol January 17, 2022, ji2100919; DOI: https://doi.org/10.4049/jimmunol.2100919
• The Amperial assay was used to measure salivary SARS-CoV-2 S1 Abs.
• IgG of 42 COVID-19 mRNA vaccinated individuals was longitudinally evaluated.
• Twenty percent of subjects experienced a 90% drop of peak IgG levels over time.
We used a noninvasive electrochemical quantitative assay for IgG Abs to SARS-CoV-2 S1 Ag in saliva to investigate the kinetics of Ab response in a community-based population that had received either the Pfizer or Moderna mRNA-based vaccine. Samples were received from a total of 97 individuals, including a subset of 42 individuals who collected samples twice weekly for 3 mo or longer. In all, >840 samples were collected and analyzed. In all individuals, salivary SARS-CoV-2 S1 IgG Ab levels rose sharply in the 2-wk period after their second vaccination, with peak Ab levels seen at 10–20 d after vaccination. We observed that 20%, 10%, and 2.4% of individuals providing serial samples had a 90%, 95%, and 99% drop, respectively, from peak levels during the duration of monitoring, and in two patients, Abs fell to prevaccination levels (5%). The use of noninvasive quantitative salivary Ab measurement can allow widespread, cost-effective monitoring of vaccine response.