Persistence of Anti-S Titre among Healthcare Workers Vaccinated with BNT162b2 mRNA COVID-19

Abstract

The COVID-19 pandemic has led to health, social and economic consequences for public health systems. As a result, the development of safe and effective vaccines, in order to contain the infection quickly became a priority. The first vaccine approved by the Italian Agency for Drugs Authorization (AIFA) was the BNT162b2 mRNA vaccine, developed by BioNTech and Pfizer (Comirnaty). Comirnaty contains a molecule called messenger RNA (mRNA), which is a nucleoside-modified RNA that encodes the SARS-CoV-2 spike glycoprotein. Even if data from phase I suggest that vaccine induced antibodies can persist for up to six months following the second shot of BNT vaccine, data regarding the real duration of immunological protection are lacking. In this study, we aimed to evaluate the duration of serological protection by detecting the presence of anti-S-RBD (receptor-binding domain) antibodies for SARS-CoV-2 among a large group of healthcare workers (HCWs) three months after vaccination. 99% of HCWs had a detectable titre of anti-S SARS-CoV-2 antibodies 90 days after the second vaccine shot. Elderly operators showed significantly lower levels of protective antibodies when compared to the younger ones, thus they could become unprotected earlier than other operators.

Determinants of the Development of SARS-CoV-2 Anti-Spike Immune-Response after Vaccination among Healthcare Workers in Egypt

“…One of the most important demographic parameters that affect the antibody response is age. An inverted association between age and post-vaccination antibody response was observed in several studies due to diminished generation of T-cell and B-lymphocyte with age [9,14,15]. In the present study, younger age was not significantly associated with antibody production.…”

“…However, the post-vaccination immune response and antibody titer remain markedly unpredictable, and many factors may affect it [8]. It had been reported to be age and gender-dependent, with higher titer in females and younger age groups [9]. Associated comorbidities that may weaken the immune response; such as cardiovascular disease, hypertension, diabetes, and obesity had been associated with lower levels of protective antibodies [10].…”

Intensity and Dynamics of Anti-SARS-CoV-2 Immune Responses after BNT162b2 mRNA Vaccination: Implications for Public Health Vaccination Strategies

“…The mRNA is translated into SARS-CoV-2 S protein, which is transiently expressed on the surface of host cells; this expression induces humoral and cellular immune responses conferring protection against COVID-19 [4,5]. Several studies have demonstrated the safety and immunogenicity of BNT162b2 vaccination [4,6,7]. However, immunogenicity varies and may not only be dependent on age and history of previous SARS-CoV-2 infection, as has been evaluated in previous studies [6,7].…”

“…The RBD is the main target of neutralizing antibodies against SARS-CoV-2 following a natural infection. Anti-nucleoprotein (N) antibodies can also develop; however, these antibodies are unable to neutralize the virus in humans [2,6].…”

“…Several studies have demonstrated the safety and immunogenicity of BNT162b2 vaccination [4,6,7]. However, immunogenicity varies and may not only be dependent on age and history of previous SARS-CoV-2 infection, as has been evaluated in previous studies [6,7]. Other factors which remain unknown could affect the intensity and duration of protection against COVID-19 (e.g., time elapsed from primary series, co-existence of other acute or chronic medical conditions, or use of specific medications).…”