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

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.

Long-Term Persistence and Relevant Therapeutic Impact of High-Titer Viral-Neutralizing Antibody in a Convalescent COVID-19 Plasma Super-Donor: A Case Report.

A convalescent, non-severe, patient with COVID-19 was enrolled as a hyper-immune plasma voluntary donor by the Immuno-Hematology and Transfusion Unit of the Regina Elena National Cancer Institute in Rome, under the TSUNAMI national study criteria. During a nearly 6-month period (May-October 2020), the patient was closely monitored and underwent four hyperimmune plasma collections. Serum SARS-CoV-2 (anti-S + anti-N) IgG and IgM, anti-S1 IgA, and neutralizing titers (NTs) were measured. Anti-SARS-CoV-2 antibody levels steadily decreased. No correlation was found between anti-S/anti-N IgG and IgM levels and viral NT, measured by either a microneutralization test or the surrogate RBD/ACE2-binding inhibition test. Conversely, NTs directly correlated with anti-S1 IgA levels. Hyperimmune donor plasma, administered to five SARS-CoV-2 patients with persistent, severe COVID-19 symptoms, induced short-term clinical and pathological improvement. Reported data suggest that high NTs can persist longer than expected, thus widening hyperimmune plasma source, availability, and potential use. In vitro RBD/ACE2-binding inhibition test is confirmed as a convenient surrogate index for neutralizing activity and patients' follow-up, suitable for clinical settings where biosafety level 3 facilities are not available. IgA levels may correlate with serum neutralizing activity and represent a further independent index for patient evaluation.

Early Onset of SARS-COV-2 Antibodies after First Dose of BNT162b2: Correlation with Age, Gender and BMI.

BACKGROUND: The first goal of the study was to analyse the antibody titre 21 days after the first dose of the BNT162b2 vaccine in a group of 252 healthcare workers (HCW). The second goal was to analyse how the antibody titre changes in correlation with age, gender and body mass index (BMI). METHODS: Participants had a nasopharyngeal swab for SARS-CoV-2 and were assessed for the presence of SARS-CoV-2 antibodies at baseline and 21 days after the BNT162b2 priming dose. RESULTS: First dose of BNT162b2 activated immune responses in 98% of the participants. Five HWC had no increase in antibody titre 21 days after the first dose. Antibody titre was greater in young (<38 years) vs. older participants (<38 vs. 47-56 p = 0.002; <38 vs. >56 p = 0.001). Higher antibody levels were detected in underweight vs. pre-obesity group (p = 0.026) and in normal-weight vs. pre-obesity group (p = 0.007). This association was confirmed after adjusting for age (p = 0.0001) and gender (p = 0.00001). CONCLUSIONS: Our study demonstrates that a single dose of BNT162b2 activates the immune response, and being young and normal-weight correlate positively with this response. Larger specifically designed clinical trials are needed to validate these results.

Initial observations on age, gender, BMI and hypertension in antibody responses to SARS-CoV-2 BNT162b2 vaccine.

BACKGROUND: Literature data suggests that age, gender and body mass index (BMI) could be associated with difference in immune responses to vaccines. The first goal of the study was to analyze the antibody titre seven days after the second dose of BNT162b2 vaccine in a group of 248 healthcare workers (HCWs). The second goal was to analyze how antibody titre changes in correlation with age, gender, BMI and hypertension. METHODS: An immunogenicity evaluation was carried out among HCWs vaccinated at the Istituti Fisioterapici Ospitalieri (IFO), Rome, Italy. All HCWs were asked to be vaccinated by the Italian national vaccine campaign at the beginning of 2021. 260 vaccinated HCWs were enrolled in the study. All eligible participants were assigned to receive the priming dose in two weeks' time and the booster dose exactly 21 days thereafter. Blood and nasopharyngeal swabs were collected at baseline and 7 days after second dose of vaccine. Quantitative measurements of IgG antibodies against S1/S2 antigens of SARS-CoV-2 were performed with a commercial chemiluminescent immunoassay. Presence of SARS-Cov-2 in nasopharyngeal swab was determined by commercial RT-PCR testing. FINDINGS: 248 HWCs were analyzed, 158 women (63.7%) and 90 men (36.3%). After the second dose of BNT162b2 vaccine, 99.5% of participants developed a humoral immune response. The geometric mean concentration of antibodies among the vaccinated subjects after booster dose (285.9 AU/mL 95% CI: 249.5-327.7) was higher than that of human convalescent sera (39.4 AU/mL, 95% CI: 33.1-46.9), with p<0.0001. Multivariate linear regression analysis of AU/mL by age, gender and BMI multivariate was performed by the inclusion of covariates. This analysis demonstrated that age (p<0.0001) and gender (p = 0.038) are statistically associated with differences in antibody response after vaccination, whereas BMI and hypertension have no statistically significant association (p = 0.078 and p = 0.52 respectively). INTERPRETATION: 99.5% of HCW developed a humoral immune response and female and young participants seem to have an increased capacity to mount humoral immune responses. BMI and hypertension seem not associated with difference in immune response to the vaccine. FUNDING: None.