Confounding Factors Influencing the Kinetics and Magnitude of Serological Response Following Administration of BNT162b2

Abstract

Background: Little is known about potential confounding factors influencing the humoral response in individuals having received the BNT162b2 vaccine. Methods: Blood samples from 231 subjects were collected before and 14, 28, and 42 days following coronavirus disease 2019 (COVID-19) vaccination with BNT162b2. Anti-spike receptor-binding-domain protein (anti-Spike/RBD) immunoglobulin G (IgG) antibodies were measured at each time-point. Impact of age, sex, childbearing age status, hormonal therapy, blood group, body mass index and past-history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were assessed by multivariable analyses. Results and Conclusions: In naïve subjects, the level of anti-Spike/RBD antibodies gradually increased following administration of the first dose to reach the maximal response at day 28 and then plateauing at day 42. In vaccinated subjects with previous SARS-CoV-2 infection, the plateau was reached sooner (i.e., at day 14). In the naïve population, age had a significant negative impact on anti-Spike/RBD titers at days 14 and 28 while lower levels were observed for males at day 42, when corrected for other confounding factors. Body mass index (BMI) as well as B and AB blood groups had a significant impact in various subgroups on the early response at day 14 but no longer after. No significant confounding factors were highlighted in the previously infected group.

Antibody responses to BNT162b2 mRNA COVID-19 vaccine and their predictors among healthcare workers in a tertiary referral hospital in Japan

“…Its influence might have been underestimated since 2 participants who had the highest titers did not have a history of previous COVID-19 but both were seropositive before vaccination, and one had had close contact with an infected individual. Again, this result is consistent with previous reports [ 11 , 12 , 15 , 16 ] and consolidates the evidence that the BNT162b2 vaccine induces more robust antibody responses in individuals previously infected with SARS-CoV-2.…”

“…In addition, all of 18 subjects who were already seropositive before vaccination showed substantial antibody responses after the 2 nd dose. These results are consistent with previous smaller-scale studies [ 7 , 8 , 11 , 12 ] and indicate that the vast majority of young-adult healthcare workers have good antibody responses following 2 doses of the BNT162b2 vaccine.…”

“…Among demographic factors, older age has been repeatedly reported to associate with reduced antibody responses after COVID-19 vaccination [ 7 , 8 , 11 , 12 ]. Our study population is younger than those in previous studies and supplement the evidence.…”

“…As the humoral responses have been shown to play essential roles in the protection against and the survival from SARS-CoV-2 infection [ 4 , 5 , 6 ], the antibody status after vaccination can provide important information to predict long-term effectiveness and to optimize the vaccination strategy. However, antibody responses after vaccination have been assessed only in small-scale studies [ 7 , 8 , 9 , 10 , 11 , 12 ]. Here, we report the antibody responses and their predictive factors in 2,015 healthcare workers who received the BNT162b2 mRNA COVID-19 vaccine.…”

Neutralizing Antibodies in COVID-19 Patients and Vaccine Recipients after Two Doses of BNT162b2

“…In the group of vaccinated individuals from the CRO-VAX HCP study [ 38 , 39 , 40 ], we evaluated the neutralizing response in a cohort of 90 volunteers, of which 60 were uninfected and 30 were previously infected by SARS-CoV-2, having received the complete dose regimen of the BNT162b2 vaccine. NAbs were measured at baseline, i.e., just before the administration of the first dose, and at 14, 28, 42 and 56 days.…”