The humoral response to COVID-19 vaccinations can predict the booster effect on health care workers-toward personalized vaccinations?

BACKGROUND: Waning immunity after the coronavirus disease 2019 (COVID-19) vaccinations creates the constant need of boosters. Predicting individual responses to booster vaccines can help in its timely administration. We hypothesized that the humoral response to the first two doses of the BNT162b2 vaccine can predict the response to the booster vaccine. METHODS: A prospective cohort of hospital health care workers (HCW) that received three doses of the BNT162b2 vaccine. Participants completed serological tests at 1 and 6 months after the second vaccine dose and 1 month after the third. We analyzed predictive factors of antibody levels after the booster using multivariate regression analyses. RESULTS: From 289 eligible HCW, 89 (31%) completed the follow-up. Mean age was 48 (±10) and 46 (52%) had daily interaction with patients. The mean (±standard deviation) antibody level 1 month after the second vaccine was 223 (±59) AU/ml, and 31 (35%) had a rapid antibody decline (>50%) in 6 months. Low antibody levels 1 month after the second vaccine and a rapid antibody decline were independent predictors of low antibody levels after the booster vaccine. CONCLUSIONS: The characteristics of the humoral response to COVID-19 vaccinations show promise in predicting the humoral response to the booster vaccines.

One-year dynamics of antibody titers after three doses of SARS-CoV-2 BNT162b2 vaccine.

BACKGROUND: A third dose of the BNT162b2 SARS-CoV-2 vaccine leads to a significant increase in antibody levels, however, concerns regarding the long-term persistence of this response exist. We assessed the humoral response for one year following vaccination. METHODS: A prospective study among immunocompetent healthcare workers (HCW) who received three doses of BNT162b2. anti-spike antibody titers were measured at six predefined timepoints, from before the second vaccine dose, and up to one year afterwards, which is 4-6 months after the third dose. HCW with a history of SARS-CoV-2 infection were excluded. RESULTS: Seventy-six HCW had all the six serological measurements. Antibody titers significantly increased shortly following the third vaccine dose, and while declining, remained higher from all previous measurements for up to six months. CONCLUSIONS: A third dose of BNT162b2 leads to a profound humoral response, which remains significantly higher than previous measurements, even after 6 months.