Rapid antibody testing for SARS-CoV-2 vaccine response in pediatric healthcare workers

Heyming, Theodore W.; Nugent, Diane; Tongol, Aprille; Knudsen-Robbins, Chloe; Hoang, Janet; Schomberg, John; Bacon, Kellie; Lara, Bryan; Sanger, Terence

Background The durability of the immune response to SARS-CoV-2 vaccination remains unknown. Our objective was to evaluate a rapid SARS-CoV-2 IgM/IgG antibody detection kit as a qualitative screen for humoral response to vaccination. Methods Study participants (n=125) included pediatric healthcare workers (HCW) who received 2 doses of BNT162b2 or mRNA-1273. Participants were tested on study entry 3/12/21-4/9/21. The mean number of days post 2nd dose was 22 (range: 17-36). Participants were tested for IgM/IgG antibodies to the SARS-CoV-2 spike protein with the RightSign COVID-19 IgG/IgM Rapid Test Cassette. ELISA/Competitive Inhibition ELISA (CI-ELISA) were subsequently run to assess for neutralization effect and SARS-CoV-2 anti-nucleocapsid IgM/IgG antibodies. Results 98.4% of participants were IgG+ and 0.8% were IgM+ on rapid RightSign testing. Of those with IgG+ results, 100% were anti-spike protein IgG+ on CI-ELISA; none who tested IgG− via the rapid test were IgG+ on CI-ELISA. All HCWs who tested RightSign positive demonstrated neutralizing capability on CI-ELISA. 1.6% demonstrated anti-nucleocapsid IgM antibodies; 5.6% demonstrated anti-nucleocapsid IgG antibodies. Conclusion The strong agreement between the rapid RightSign IgG results and confirmatory CI-ELISA testing suggests this test may be used to assess for positive, and neutralizing, antibody response to SARS-CoV-2 mRNA vaccination.