Search

Background Since the introduction of BNT162b2 mRNA COVID-19 vaccine by Pfizer in late 2020, efficacy and immunogenicity waning of COVID-19 vaccines was reported, and decision making regarding a booster remains a top priority worldwide, a decision that should be made based on breakthrough infection rate and antibody titer decline overtime. Methods We conducted a 5-month longitudinal prospective study involving vaccinated healthcare personnel, who were tested monthly for antibody titer, and sampled biweekly and on clinical indication for SARS-COV-2 polymerase chain reaction (PCR), to determine antibody decline and breakthrough infection. Results 100 participants were recruited to the study. Antibody titer reached the climate after one month of the second dose of the vaccine, and declined rapidly thereafter: the median antibody levels were 895; 22,266; 9,682; 2,554 and 1,401 AU/ml in the day of the second dose, and in one month interval thereafter, respectively. In other words, four months after vaccination, the mean antibody level was 6% of the peak levels. During the study period, 4 breakthrough infections were diagnosed, 2 of which were asymptomatic, and the remaining two were mild cases; sharp elevation of antibody titer was seen after infection. Conclusion Antibody titer drops rapidly one month after the second dose of the vaccine. All infections within the study period were mild or asymptomatic, after which titer elevations were seen.

Background Changing patterns of vaccine breakthrough can clarify vaccine effectiveness. Aim To compare breakthrough infections during a SARS-CoV-2 Delta wave vs unvaccinated inpatients, and an earlier Alpha wave. Methods In an observational multicentre cohort study in Israel, hospitalised COVID-19 patients were divided into three cohorts: breakthrough infections in Comirnaty-vaccinated patients (VD; Jun–Aug 2021) and unvaccinated cases during the Delta wave (ND) and breakthrough infections during an earlier Alpha wave (VA; Jan–Apr 2021). Primary outcome was death or ventilation. Results We included 343 VD, 162 ND and 172 VA patients. VD were more likely older (OR: 1.06; 95% CI: 1.05–1.08), men (OR: 1.6; 95% CI: 1.0–2.5) and immunosuppressed (OR: 2.5; 95% CI: 1.1–5.5) vs ND. Median time between second vaccine dose and admission was 179 days (IQR: 166–187) in VD vs 41 days (IQR: 28–57.5) in VA. VD patients were less likely to be men (OR: 0.6; 95% CI: 0.4–0.9), immunosuppressed (OR: 0.3; 95% CI: 0.2–0.5) or have congestive heart failure (OR: 0.6; 95% CI: 0.3–0.9) vs VA. The outcome was similar between all cohorts and affected by age and immunosuppression and not by vaccination, variant or time from vaccination. Conclusions Vaccination was protective during the Delta variant wave, as suggested by older age and greater immunosuppression in vaccinated breakthrough vs unvaccinated inpatients. Nevertheless, compared with an earlier post-vaccination period, breakthrough infections 6 months post-vaccination occurred in healthier patients. Thus, waning immunity increased vulnerability during the Delta wave, which suggests boosters as a countermeasure.

IMPORTANCE: Identification of adverse events after vaccination increases awareness of vaccine-associated complications, leading to early diagnosis and treatment. Evidence remains scarce on the association between the BNT162b2 messenger RNA (mRNA) COVID-19 vaccine (Pfizer-BioNTech) and sudden sensorineural hearing loss (SSNHL). OBJECTIVE: To assess the association between the BNT162b2 mRNA COVID-19 vaccine and SSNHL. DESIGN, SETTING, AND PARTICIPANTS: This retrospective, population-based cohort study was performed from December 20, 2020, to May 31, 2021, using data from the largest health care organization in Israel. Patients 16 years or older who received the first vaccine dose between December 20, 2020, and April 30, 2021, and the second vaccine dose between January 10, 2021, and April 30, 2021, were included. EXPOSURES: Receipt of first and second BNT162b2 mRNA COVID-19 vaccine doses. MAIN OUTCOMES AND MEASURES: The main outcome was SSNHL based on International Classification of Diseases, Ninth Revision (ICD-9) codes in conjunction with concurrent prednisone dispensing. Observed cases of SSNHL, occurring within 21 days after each of the first and second vaccine doses, were compared with the expected cases based on the experience of the population in 2018 and 2019. Standardized incidence ratios (SIRs) and attributable risks were computed. RESULTS: Overall, 2 602 557 patients (mean [SD] age, 46.8 [19.6] years; 51.5% female) received the first dose of BNT162b2 mRNA COVID-19 vaccine, with 91 cases of SSNHL reported. Of these patients, 2 441 719 (93.8%) received the second vaccine dose, with 79 cases of SSNHL reported. The age- and sex-weighted SIRs were 1.35 (95% CI, 1.09-1.65) after the first vaccine dose and 1.23 (95% CI, 0.98-1.53) after the second vaccine dose. After the first vaccine dose, the estimated SIRs were more pronounced in female patients aged 16 to 44 years (SIR, 1.92; 95% CI, 0.98-3.43) and female patients 65 years or older (SIR, 1.68; 95% CI, 1.15-2.37). After the second vaccine dose, the highest estimated SIR was observed in male patients 16 to 44 years (SIR, 2.45; 95% CI, 1.36-4.07). The attributable risks were generally small, and the results were similar when 2019 was used as a reference to estimate the expected number of SSNHL cases. CONCLUSIONS AND RELEVANCE: This study suggests that the BNT162b2 mRNA COVID-19 vaccine might be associated with increased risk of SSNHL; however, the effect size is very small. Further studies are warranted to establish this possible association.

Background: An excess risk of Bell's palsy has been suggested after mRNA vaccines. We examined the association between the BNT162b2 mRNA COVID-19 vaccine and Bell's palsy. Methods: Using the database of the largest healthcare provider in Israel, we retrieved data from different periods in 2018-2021. Observed cases of Bell's palsy occurring within 21-days after the first vaccine dose and within 30-days after the second vaccine dose were compared to the expected cases, based on the experience of the population in 2019. Standardized incidence ratios (SIRs) and attributable risks (ARs) were computed. Findings: Overall, 132 cases of Bell's palsy were reported in 2,594,990 vaccinees with the first dose, and 152 cases in 2,434,674 vaccinees after the second dose. The age and sex weighted SIRs were 1.36(95% CI, 1.14-1.61) and 1.16(0.99-1.36) after the first and second vaccine dose, respectively. SIRs tended to be higher in older age groups after the first and second vaccine doses. The estimates were more pronounced in older females after the first vaccine dose; SIR=1.71(1.10-2.54) at age 45-64, and 2.51(1.65-3.68) at age ≥65 years. The highest AR was 4.46 per 100,000 vaccinees detected in females aged ≥65 years. In patients with previous history of Bell's palsy, only 4 cases of Bell's palsy were reported in 7,567 vaccinees and 10 cases in 7,045 vaccinees after the first and the second dose, respectively. The age and sex weighted SIRs were 1.15(0.36-2.76) and 2.15(1.09-3.83) after the first and second vaccine dose, respectively. Interpretation: This study suggests that the BNT162b2 mRNA COVID-19 vaccine might be associated with increased risk of Bell's palsy. The small estimated attributable risks suggest that the impact on public health is relatively minor. The benefits of vaccinations explicitly outweigh the possible link to Bell's palsy that has high recovery rate if timely treated with corticosteroids. Funding: No external funding was available for this study.