BNT162b2 COVID-19 vaccine and correlates of humoral immune responses and dynamics: a prospective, single-centre, longitudinal cohort study in health-care workers

Abstract

Background Concurrent with the Pfizer–BioNTech BNT162b2 COVID-19 vaccine roll-out in Israel initiated on Dec 19, 2020, we assessed the early antibody responses and antibody kinetics after each vaccine dose in health-care workers of different ages and sexes, and with different comorbidities. Methods We did a prospective, single-centre, longitudinal cohort study at the Sheba Medical Centre (Tel-Hashomer, Israel). Eligible participants were health-care workers at the centre who had a negative anti-SARS-CoV-2 IgG assay before receiving the first dose of the intramuscular vaccine, and at least one serological antibody test after the first dose of the vaccine. Health-care workers with a positive SARS-CoV-2 PCR test before vaccination, a positive anti-SARS-CoV-2 IgG serology test before vaccination, or infection with COVID-19 after vaccination were excluded from the study. Participants were followed up weekly for 5 weeks after the first vaccine dose; a second dose was given at week 3. Serum samples were obtained at baseline and at each weekly follow-up, and antibodies were tested at 1–2 weeks after the first vaccine dose, at week 3 with the administration of the second vaccine dose, and at weeks 4–5 (ie, 1–2 weeks after the second vaccine dose). Participants with comorbidities were approached to participate in an enriched comorbidities subgroup, and at least two neutralising assays were done during the 5 weeks of follow-up in those individuals. IgG assays were done for the entire study population, whereas IgM, IgA, and neutralising antibody assays were done only in the enriched comorbidities subgroup. Concentrations of IgG greater than 0·62 sample-to-cutoff (s/co) ratio and of IgA greater than 1·1 s/co, and titres of neutralising antibodies greater than 10 were considered positive. Scatter plot and correlation analyses, logistic and linear regression analyses, and linear mixed models were used to investigate the longitudinal antibody responses. Findings Between Dec 19, 2020, and Jan 30, 2021, we obtained 4026 serum samples from 2607 eligible, vaccinated participants. 342 individuals were included in the enriched comorbidities subgroup. The first vaccine dose elicited positive IgG and neutralising antibody responses at week 3 in 707 (88·0%) of 803 individuals, and 264 (71·0%) of 372 individuals, respectively, which were rapidly increased at week 4 (ie, 1 week after the second vaccine dose) in 1011 (98·4%) of 1027 and 357 (96·5%) of 370 individuals, respectively. Over 4 weeks of follow-up after vaccination, a high correlation ( r =0·92) was detected between IgG against the receptor-binding domain and neutralising antibody titres. First-dose induced IgG response was significantly lower in individuals aged 66 years and older (ratio of means 0·25, 95% CI 0·19–0·31) and immunosuppressed individuals (0·21, 0·14–0·31) compared with individuals aged 18·00–45·99 years and individuals with no immunosuppression, respectively. Thi...

Occurrence of BNT162b2 Vaccine Adverse Reactions Is Associated with Enhanced SARS-CoV-2 IgG Antibody Response

“…Only one individual among the questionnaire responders was previously diagnosed with a COVID-19 infection and was excluded. In addition, no quantitative analysis of neutralizing antibodies was performed, however, several studies showed a positive correlation between IgG against the receptor-binding domain (RBD) and neutralizing antibody titers [14,15].…”

Protection of BNT162b2 Vaccine Booster against Covid-19 in Israel

“…The protection gained by the booster shot was not expected to reach its maximal capacity immediately after vaccination but rather to build up during the subsequent week. 10 , 11 At the same time, during the first days after vaccination, substantial behavioral changes in the booster-vaccinated population are possible (Fig. S1 in the Supplementary Appendix , available with the full text of this article at NEJM.org).…”

Nationwide Seroprevalence of SARS-CoV-2 IgG Antibodies among Four Groups of Primary Health-Care Workers and Their Household Contacts 6 Months after the Initiation of the COVID-19 Vaccination Campaign in France: SeroPRIM Study Protocol

“…Vaccination of HCWs has also been associated with a substantial reduction in the number of COVID-19 cases among household contacts, which is consistent with the effectiveness of vaccination for preventing transmission [8]. Although neither of the studies [6,7] specifically assessed the rates of asymptomatic SARS-CoV-2 infection, recent studies suggest that asymptomatic SARS-CoV-2 infection may be frequent in vaccinated frail older patients [9] and less frequent, yet observable, in the general population [10]. These results support the use of vaccines in addressing the COVID-19 pandemic, but it is not clear whether the immune protection will last or whether vaccine boosters will be required to provide long-lasting protection.…”

“…The first US multisite test-negative design vaccine effectiveness study among HCWs found a single dose of an mRNA vaccine (Pfizer-BioNTech or Moderna COVID-19) to be 82% effective against symptomatic COVID-19, and two doses to be 94% effective [6]. The detection of neutralizing and IgG antibodies in 96.5% and 99.9% of vaccinated HCWs in an Israeli study suggests that the Pfizer-BioNTech BNT162b2 COVID-19 vaccine elicits a significantly higher and more robust antibody response compared to natural infection [7]. Vaccination of HCWs has also been associated with a substantial reduction in the number of COVID-19 cases among household contacts, which is consistent with the effectiveness of vaccination for preventing transmission [8].…”