Introduction: COVID-19 was classified as a global pandemic by the WHO in March, 2020. As the vaccine distribution is in progress, ongoing analyses verifying their efficacy on antibody development is critical. This research investigates the time period for IgG, IgM, and neutralizing antibody production.
Methods: 80 participants (ages 23 – 100) were administered the Pfizer vaccine (January 17, 2021). POC lateral flow immunoassays were performed on days 0, 14, 21, 28, and 42 after vaccination and the AFI-6000 Fluorescence immunoassay analyzer was used to detect neutralizing antibodies on days 28 and 42.
Results: By day 14 after dose 1, participants (≤70 years) had a much higher antibody development (69% of participants) than those ≥70 (16%). A pattern of antibody response decreasing as age increased was observed. However, 3 weeks after the second dose, only two participants were antibody negative. The percentage of neutralizing antibodies (NAb) developed post-immunization was also assayed. Similarly to before, all (but two) ≤70 developed NAb 7 days after dose two, compared to 50%, 71-80 y.o, 33%, 81-90 y.o, and 11%, 90-100 y.o in the study. By day 21 after dose 2, participants who developed NAb rose to 83% (71-80), 71% (81-90), and 50% (90-100).
Conclusions: More research should be done to conclude whether those 80+ will require a third booster or a more concentrated dose, as in the case of the influenza vaccine. Future work will analyze a larger sample size and correlations between medical history and the duration for antibody development.