Antibody Persistence 6 Months Post-Vaccination with BNT162b2 among Health Care Workers

Abstract

Background: We present immunogenicity data 6 months after the first dose of BNT162b2 in correlation with age, gender, BMI, comorbidities and previous SARS-CoV-2 infection. Methods: An immunogenicity evaluation was carried out among health care workers (HCW) vaccinated at the Istituti Fisioterapici Ospitalieri (IFO). All HCW were asked to be vaccine by the national vaccine campaign at the beginning of 2021. Serum samples were collected on day 1 just prior to the first dose of the vaccine and on day 21 just prior to the second vaccination dose. Thereafter sera samples were collected 28, 49, 84 and 168 days after the first dose of BNT162b2. Quantitative measurement of IgG antibodies against S1/S2 antigens of SARS-CoV-2 was performed with a commercial chemiluminescent immunoassay. Results: Two hundred seventy-four HWCs were analyzed, 175 women (63.9%) and 99 men (36.1%). The maximum antibody geometric mean concentration (AbGMC) was reached at T2 (299.89 AU/mL; 95% CI: 263.53–339.52) with a significant increase compared to baseline (p < 0.0001). Thereafter, a progressive decrease was observed. At T5, a median decrease of 59.6% in COVID-19 negative, and of 67.8% in COVID-19 positive individuals were identified with respect to the highest antibody response. At T1, age and previous COVID-19 were associated with differences in antibody response, while at T2 and T3 differences in immune response were associated with age, gender and previous COVID-19. At T4 and T5, only COVID-19 positive participants demonstrated a greater antibody response, whereas no other variables seemed to influence antibody levels. Conclusions: Overall our study clearly shows antibody persistence at 6 months, albeit with a certain decline. Thus, the use of this vaccine in addressing the COVID-19 pandemic is supported by our results that in turn open debate about the need for further boosts.

Patients with Liver Cirrhosis Show High Immunogenicity upon COVID-19 Vaccination but Develop Premature Deterioration of Antibody Titers

“…The most interesting point of this study refers to the kinetics of the antibody titers. In previous reports in healthy participants, antibody titers stayed relatively stable in the first months after vaccination, although a certain decay was observed [ 26 , 27 , 28 , 29 , 30 , 31 ]. In our cohort, the dynamics of antibody titers also showed relative stability in the group of HCW.…”

An update on drugs with therapeutic potential for SARS-CoV-2 (COVID-19) treatment

“…Moreover, multiple studies have shown waning immunity acquired after vaccination, especially in immunocompromised patients, for example those undergoing hemodialysis or cytotoxic cancer drug treatment. This contributes to an increasing number of breakthrough infections ( Shroff et al, 2021 ; Juno and Wheatley, 2021 ; Goldberg et al, 2021 ; Fowlkes et al, 2021 ; Davidovic et al, 2021 ; Campo et al, 2021 ). Currently, several countries have developed various strategies to tackle this problem, among which, additional doses of COVID-19 vaccines have shown to be safe and efficient in boosting immune response ( Yue et al, 2021 ; Falsey et al, 2021 ; Dekervel et al, 2021 ; Choi et al, 2021 ; Barros-Martins et al, 2021 ).…”

Characterization of the significant decline in humoral immune response six months post-SARS-CoV-2 mRNA vaccination: A systematic review

“…Among the four journal articles included in this study, two reported that seropositive groups had a larger percent decline in Ab titers from peak compared with seronegative groups. 10,12 This is possibly due to higher peak values making Ab catabolism more pronounced in seropositive groups. 12 Another possible explanation is due to timing, as seropositive groups reach peak Ab titers right after the first dose.…”

“…9 Such vulnerability is correlated to the significant decline in anti-SARS-CoV-2 antibodies (Abs) over time. [10][11][12] This waning humoral response could lead to breakthrough infections, thus highlighting the potential role of serologic testing to assess vaccine immunogenicity and protection efficacy. While the role of T cells and B memory cells from vaccine-induced immunity has yet to be fully elucidated, multiple studies showed that Ab levels directly correlate with risk of vaccine reinfection and breakthrough, with low levels of anti-SARS-CoV-2 IgG in patients with infections correlating with high viral load and duration of viral shedding.…”