Antibody response to first and second dose of BNT162b2 in a cohort of characterized healthcare workers

Abstract

Background: Vaccine-induced population immunity is a key global strategy to control coronavirus disease 2019 (COVID-19). The rapid implementation and availability of several COVID-19 vaccines is now a global health-care priority but more information about humoral responses to single- and double-dose vaccine is needed Methods: 163 health care workers (HCW) of the Padua University Hospitals, who underwent a complete vaccination campaign with BNT162b2 vaccine were asked to collect serum samples at 12 (t12) and 28 (t28) days after the first inoculum to allow the measurement of SARS-CoV-2 Antibodies (Ab) using chemiluminescent assays against the spike (S) protein and the Receptor Binding Domain (RBD) of the virus, respectively. Results: Significant differences were found at t12 for infection-naive and subjects with previous-natural infection who present higher values of specific antibodies, while no significant differences have been found between t12 and t28. No statistically significant difference was found between male and female, while lower Ab levels have been observed in subjects older than 60 years at t12 but not at t28. Conclusions: Our study confirms observed differences in vaccine responses between infection-naive and subjects with previous natural infection at t12 but not for a longer time. The influence of sex and age deserves further studies, even if the relationship with age seems particularly significant.

Antibody titres decline 3-month post-vaccination with BNT162b2

“…below 3 months. [2][3][4][5][6] Therefore, a longer follow-up period is needed to assess the antibody kinetics in individuals after a two-dose regimen of BNT162b2. These data are important, especially since the question about a third dose has been raised by the pharmaceutical industries which will led to important societal, logistical and economical consequences.…”

Assessment of salivary antibody response to BNT162b2 mRNA COVID‐19 vaccination

“…recent studies point at the development of an efficient and robust systemic humoral response following vaccination, that can be monitored using serological immunoassays registered for quantitative measurement of anti-SARS-CoV-2 S antibodies in serum. [1][2][3][4] The humoral immune response might be expected not only in blood but also in the mucosa and salivary glands. Since SARS-CoV-2 is mainly transmitted through direct or indirect contact with mucosal membranes, the presence of mucosal antibodies might directly prevent or limit virus transmission.…”

Anti-spike protein receptor-binding domain IgG levels after COVID-19 infection or vaccination against SARS-CoV-2 in a seroprevalence study

“…Still, in the model of anti-S-RBD IgG after vaccination that was mostly based on data from older people, the half-life was somewhat shorter, but not significantly, and it could be also due to the short observation period of vaccinated individuals as initially more rapid decline occurs compared with later time period [14, 20, 21]. Nevertheless, as after vaccination older people have lower anti-S-RBD IgG peak level, also found by others [22-24], their antibody levels will be lower for some time compared with younger individuals until equalizing [24]. Due to limited data so far, further studies are warranted to determine whether the older age groups, at the highest risk of severe disease, are also at the risk of faster decline of IgG after vaccination.…”