Reactogenicity among health care workers following a BNT162b2 or mRNA-1273 second dose after priming with a ChAdOx1 nCOV-19 vaccine

ObjectivesIn March 2021, French authorities recommended a heterologous second dose of the mRNA vaccine for persons aged <55 years, with administration 9 to 12 weeks after the first dose of ChAdOx1 nCoV-19. This recommendation was despite a lack of data on the reactogenicity and safety of the regimen. Since then, several studies have shown an acceptable short-term safety profile of ChAdOx1 nCoV-19 and BNT162b2 heterologous vaccination, although some transient increased reactogenicity has been described.MethodsWe performed a single-centre prospective observational cohort study among health care workers (HCWs) at a tertiary care hospital to assess the reactogenicity of the BNT162b2 and mRNA-1273 vaccines administered as a second dose in participants primed with ChAdOx1 nCoV-19.ResultsAmong 1184 HCWs, 356 (30%) agreed to participate. Of the participants, 32.3% were male, and the mean age was 35 years (standard deviation: 10.1 years). Of the participants, 229 received BNT162b2 and 127 received mRNA-1273. A systemic reaction was observed in 130 of 229 (56.8%) and 100 of 127 (78.7%) HCWs, respectively. Injection site reactions were generally limited (grade 1 or 2 in 163 of 229 (97.6%) and 90 of 127 (85.7 %) HCWs, respectively). After adjustment for age, sex, and HCW role, receiving the mRNA-1273 vaccine was associated with higher reactogenicity with more grade 3 side effects (adjusted OR (aOR): 3.34; 95% CI, 1.91–5.85), more systemic symptoms (aOR: 2.82; 95% CI, 1.69–4.7), and not being able to work (aOR: 8.35; 95% CI, 3.78–18.44) compared with receiving the BNT162b2 vaccine.DiscussionAmong patients receiving the mRNA1273 vaccine as a second dose, our study confirms good tolerance of the heterologous schedule with a higher risk of short-term side effects in comparison with patients receiving the BNT162b2 vaccine.     

Comparison of Antibody Response Elicited by ChAdOx1 and BNT162b2 COVID-19 Vaccine

BackgroundChAdOx1 and BNT162b2 vaccines are currently commonly used against coronavirus disease 2019 worldwide. Our study was designed to determine the serostatus and relative levels of anti-S and neutralizing antibodies in patients who were administered either ChAdOx1 or BNT162b2 vaccine. In addition, we investigated whether the antibody response to each vaccine differed according to sex and age.MethodsHealthcare workers (HCWs) at a general hospital who were vaccinated with two doses of either ChAdOx1 or BNT162b2 were invited to participate in this prospective cohort study. Blood samples of HCWs vaccinated with both ChAdOx1 doses over a period of 12 weeks were collected at weeks 4 and 8 post first vaccination and 2 weeks post second vaccination. Blood samples of HCWs vaccinated with BNT162b2 were collected in the third week after the first dose, and the second dose was then administered on the same day; two weeks post second dose (5 weeks after the first dose), blood samples were collected to assess the antibody response. The titers of anti-S antibodies against the severe acute respiratory syndrome coronavirus 2 spike (S) protein receptor-binding domain and the neutralizing antibodies in the collected blood were evaluated.ResultsOf the 309 HCWs enrolled in the study, 205 received ChAdOx1 and 104 received BNT162b2. Blood samples from participants receiving either the ChAdOx1 or BNT162b2 vaccine exhibited substantial anti-S and neutralizing antibody seropositivity subsequent to the second dose. All participants (100%) from both vaccine groups were seropositive for anti-S antibody, while 98% (201/205) of ChAdOx1-vaccinated individuals and 100% (104/104) of BNT162b2-vaccinated individuals were seropositive for neutralizing antibodies. The median levels of anti-S and neutralizing antibodies were significantly higher in the BNT162b2-vaccinated group than the ChAdOx1-vaccinated group; in particular, anti-S antibody titers of 1,020 (interquartile range, 571.0–1,631.0) U/mL vs. 2,360 (1,243–2,500) U/mL, P < 0.05, were recorded for the ChAdOx1 and BNT162b2 groups, respectively, and neutralizing antibody titers of 85.0 (65.9–92.1%) vs. 95.8 (94.4–96.6%), P < 0.05, were recorded for the ChAdOx1 and BNT162b2 groups, respectively. In the ChAdOx1 vaccine group, the neutralizing antibody level was significantly higher in women than in men (85.7 [70.3–92.5%] vs. 77.7 [59.2–91.0%], P < 0.05); however, the neutralizing antibody titer in the BNT162b2 vaccine group did not vary between the two sexes (95.9 [95.2–96.6%] vs. 95.2 [93.5–96.3%], P = 0.200). Analysis of the correlation of antibody profiles with age revealed that the levels of anti-S antibodies and signal inhibition rate (SIR) of neutralizing antibodies decreased significantly with age.ConclusionBoth the ChAdOx1- and BNT162b2-vaccinated groups showed high seropositivity for anti-S and neutralizing antibodies. The SIR of neutralizing antibodies in the ChAdOx1 vaccine group was higher in women than in men. Enhanced antibody responses were observed in participants vaccinated with BNT162b2 compared to those vaccinated with the ChAdOx1 vaccine.     

Adverse Reactions Following the First Dose of ChAdOx1 nCoV-19 Vaccine and BNT162b2 Vaccine for Healthcare Workers in South Korea

BackgroundWe performed a prospective survey on the adverse reactions following the first dose of two types of vaccines against coronavirus disease 2019 (COVID-19) in healthcare workers (HCWs) in South Korea.MethodsHCWs at a tertiary referral hospital in Seoul, South Korea, received a chimpanzee adenovirus-vectored vaccine (ChAdOx1 nCoV-19) or an mRNA-based vaccine (BNT162b2) between March 5 and March 26, 2021. The HCWs were asked to report adverse reactions through a mobile self-report questionnaire for three days after vaccination.ResultsA total of 7,625 HCWs received the first dose of ChAdOx1 or BNT162b2 vaccine during the study period. Of them, 5,866 (76.9%) HCWs (ChAdOx1, n = 5,589 [95.3%]; BNT162b2, n = 277 [4.7%]) participated at least once in the survey, of whom 77% were female and 86% were younger than 50 years. The overall adverse reaction rate was 93% in the ChAdOx1 group and 80% in the BNT162b2 group (P < 0.001). Both local and systemic reactions were more commonly reported in the ChAdOx1 group, and the difference was larger in systemic reactions such as fever and fatigue. In the ChAdOx1 group, the incidence of adverse reactions was significantly higher in females and those in the younger age groups, while the BNT162b2 group showed such difference according to age.ConclusionIn our prospective survey, vaccine-associated adverse reactions were more commonly reported in the ChAdOx1 group than in the BNT162b2 group. Females and younger age groups experienced vaccine-associated adverse reactions more frequently.     

Postvaccination infections among staff of a tertiary care hospital after vaccination with severe acute respiratory syndrome coronavirus 2 vector and mRNA-based vaccines

ObjectivesThe identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen or RNA in respiratory specimens ≥14 days after administration of all recommended doses of authorized coronavirus disease 2019 (COVID-19) vaccines is defined as breakthrough infection. In the present investigation, mRNA and vector-based SARS-CoV-2 vaccines were analysed with respect to postvaccination infections in vaccinated hospital employees.MethodsA total of 8553 staff members were vaccinated with BNT162b2 (47%) or ChAdOx1-S (53%) between January and May 2021. In a retrospective observational cohort study, incidence of SARS-CoV-2 postvaccination infections was analysed in relation to demographic data, viral load, virus variants, vaccine brand and vaccination status at time of positive PCR test (fully vaccinated: ≥14 days since second dose; partially vaccinated: >21 days since first, but <14 days after second dose; insufficiently vaccinated: <22 days since first dose).ResultsWithin the follow-up period, ending on 31 July 2021, person-time at risk-adjusted monthly rates for SARS-CoV-2 postvaccination infections were 0.18% (BNT162b2) and 0.57% (ChAdOx1-S) for insufficiently vaccinated, 0.34% (BNT162b2) and 0.32% (ChAdOx1-S) for partially vaccinated and 0.06% (BNT162b2) and 0.04% (ChAdOx1-S) for fully vaccinated participants. The two vaccine types did not differ with respect to hazard ratios for any of the respective postvaccination infection types. No cases of COVID-19-related hospitalizations or deaths were reported. Genotyping of positive PCR specimens revealed 42 variants of concern: B.1.1.7 (Alpha variant; n = 34); B.1.351 (Beta variant; n = 2), B.1.617.2 (Delta variant; n = 6).ConclusionsBNT162b2 and ChAdOx1-S are both effective in preventing breakthrough infections; however, it seems important, that all recommended vaccine doses are administered.     

Decline of antibody titres 3 months after two doses of BNT162b2 in non-immunocompromised adults

ObjectiveTo assess the antibody response in non-immunocompromised adults after two doses of BNT162b2.MethodsProspective, single-centre observational study in non-immunocompromised adults aged 18 years or more who received two doses of BNT162b2. The study contemplates analyses of serum samples collected 1.5, 3, 6, 9 and 12 months after the second dose of BNT162b2; results of the 1.5- and 3-month time-points are presented in this report. Antibodies against the receptor binding domain of the S1 subunit of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (anti-RBD antibodies) were measured using a commercial quantitative immunoassay. A threshold of 4160 AU/mL (corresponding to an ID₅₀ of 1:250) was used as surrogate marker for serum neutralizing activity.ResultsOf 273 hospital workers who received two doses of BNT162b2, 260 (95%) agreed to participate in the study; 2/260 (0.8%) were excluded because of immunocompromised conditions. At the time of this report, 230/258 (89%) participants (mean age 46.0 years (SD 11.4 years); 143/230 (62%) female; 87/230 (38%) male) had completed 3 months of follow up after the second dose of BNT162b2. Thirty-six (16%) of the 230 had documented mild SARS-CoV-2 infection before receiving the first dose of BNT162b2. Median (interquartile range (IQR)) anti-RBD titres 1.5 months after vaccination were 9356 (5844–16 876) AU/mL; 3 months after vaccination, median anti-RBD titres had declined to 3952 (2190–8561) AU/mL (p < 0.001). Of 199/230 (86.5%) participants who had anti-RBD titres above 4160 AU/mL 1.5 months after the second dose of BNT162b2, only 95/230 (41%) maintained anti-RBD titres above this level 3 months after vaccination (p < 0.001).ConclusionsThe decline of anti-RBD antibodies 3 months after the second dose of BNT162b2 is of concern because it raises the possibility of a short-lived humoral immunity after vaccination. Booster doses of BNT162b2 might be required to maintain high titres of anti-RBD antibodies over time.     

Early antibody response in health-care professionals after two doses of SARS-CoV-2 mRNA vaccine (BNT162b2)

ObjectivesData on the immune response after two doses of BNT162b2 are so far limited. Previously infected individuals were excluded from pivotal clinical trials and the optimum dose regimen in this population has not been clearly studied. The CRO-VAX HCP study aims to investigate the early antibody response in a population of health-care professionals having received two doses of the BNT162b2 mRNA coronavirus disease 2019 (COVID-19) vaccine.MethodsThe CRO-VAX HCP study is a multicentre, prospective, interventional study conducted in several sites in Belgium. The study included 231 health-care professional volunteers who received the two-dose regimen of the BNT162b2 mRNA COVID-19 vaccine. Of these, 73 were previously infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and 158 were uninfected and seronegative. In the first group, blood samples were collected at baseline and after 2, 4, 7, 10, 14, 21 and 28 days. In the second group, samples were obtained at baseline and after 14 and 28 days. Antibodies against the SARS-CoV-2 nucleocapsid and the receptor binding domain of the S1 subunit of the spike protein were measured in all individuals at different time-points.ResultsIn uninfected individuals, 95.5% (95% CI 91.0%–98.2%) developed anti-spike antibodies after 14 days and a 24.9-fold rise (95% CI 21.4%–28.9%) in antibody titre was observed after the second dose. In previously infected individuals, peak antibody response was reached after 7 days (i.e. 6347 U/mL) and the second dose did not lead to significantly higher antibody titres (i.e. 8856–11 911 U/mL). Antibody titres were higher in previously infected individuals.ConclusionsThis study supports the concept that a single dose of BNT162b2 would be sufficient in previously infected individuals.     

The impact of COVID-19 vaccination programme in the Republic of San Marino: Focus on effectiveness of Gam-Covid-Vac

ObjectiveThe adenovirus-based vaccine Gam-COVID-Vac (Sputnik V) showed promising effectiveness in a phase 3 clinical trial; however, data concerning its impact at a population level are scarce. The Republic of San Marino (RSM) conducted a SARS-CoV-2 vaccination programme mainly based (>80%) on Gam-COVID-Vac. Our aims were to investigate the impact of Gam-COVID-Vac vaccination programme and its effectiveness in a retrospective observational study based on the entire RSM population aged ≥12 years.MethodsWe calculated the incidence rate and the vaccine effectiveness (VE) in the entire RSM population not previously infected, against SARS-CoV-2 infection and COVID-19–related hospitalization, from 25 February to 1 October 2021, considering any vaccine and separately according to the vaccine used. Vaccine effectiveness was calculated using a multivariable negative binomial regression model as 1-Incidence Rate Ratio.ResultsDuring the study period, 21 568/28 791 (74.9%) not previously infected subjects received at least one dose of the Gam-COVID-Vac (84%) or BNT162b2, vaccines with 98% completing the vaccination schedule. Overall, 1634 SARS-CoV-2 infections and 166 COVID-19-related hospitalizations were observed with 17 COVID-19-related deaths reported. Incidence rates of SARS-CoV-2 infection and COVID-19-related hospitalization were 7.11 and 0.49/100 000 person-days in the fully vaccinated population, respectively. The adjusted overall VE was 67.6% (95% CI: 61.8–72.5) against SARS-CoV-2 infection and 87.9% (95% CI: 77.4–93.5) against COVID-19-related hospitalizations.Gam-COVID-Vac against SARS-CoV-2 infection VE peaked 91.8% (95% CI: 86.3–95.1) in the first bimester from the second dose, declining to 57.8% (95% CI: 42.2–69.2) at 6 months. Protection against hospitalization with COVID-19 was overall 91.6% (95% CI: 81.5–96.2), with no relevant waning trend over time.DiscussionOur study demonstrated the effectiveness of overall vaccination (Gam-COVID-Vac [84%] and BNT162b2 [16%]) in the prevention SARS-CoV-2 infection (pre-Omicron variant), waning over time but still with sustainable effectiveness against COVID-19-related hospitalization in the Republic of San Marino.     

Humoral serological response to the BNT162b2 vaccine after allogeneic haematopoietic cell transplantation

ObjectivesTo assess the humoral immune response to the BNT162b2 vaccine after allogeneic haematopoietic cell transplantation (HCT).MethodsThis is a prospective cohort study. The SARS-CoV-2 IgGII Quant (Abbott©) assay was performed 4–6 weeks after the second BNT162b2 vaccine for quantitative measurement of anti-spike antibodies.ResultsThe cohort included 106 adult patients. Median time from HCT to vaccination was 42 (range 4–439) months. Overall, 15/106 (14%, 95% confidence interval (CI) 7–21%) were seronegative despite vaccination, 14/52 patients on immunosuppression (27%, 95%CI 19–35%) compared to only 1/54 patients off immunosuppression (1.8%, 95%CI 1–4%) (p 0.0002). The proportion of seronegative patients declined with time; it was 46% (6/13) during the first year, 12.5% (3/24) during the second year and 9% (6/69) beyond 2 years from transplant. Patients with acute graft-versus-host disease (GVHD) (odds ratio (OR) 3.3, 95%CI 0.97–11.1, p 0.06) and moderate to severe chronic GVHD (OR 5.9, 95%CI 1.2–29, p 0.03) were more likely to remain seronegative. Vaccination was well tolerated by most patients. However, 7% (7/106) reported that GVHD-related symptoms worsened within days following vaccination.ConclusionA significant proportion of allogeneic HCT recipients receiving immunosuppression demonstrated an inadequate humoral response to the BNT162b2 vaccine. These patients should be recognized and instructed to take appropriate precautions. Recipients who were off immunosuppression had a humoral response that was comparable to that of the general population.     

The effect of a third-dose BNT162b2 vaccine on anti-SARS-CoV-2 antibody levels in immunosuppressed patients

ObjectivesThe recent surge in coronavirus disease 2019 cases led to the consideration of a booster vaccine in previously vaccinated immunosuppressed individuals. However, the immunogenic effect of a third-dose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in immunosuppressed patients is still unknown.MethodsThis was an observational cohort study of 279 previously vaccinated immunosuppressed patients followed at a single tertiary hospital in Israel. Patients were administered a third dose of the Pfizer-BioNTech mRNA vaccine (BNT162b2) between July 14 and July 21, 2021. Levels of IgG antibodies against the spike receptor-binding domain of SARS-CoV-2 were measured 3 to 4 weeks after vaccination.ResultsOf the cohort of 279 patients, 124 (44.4%) had haematologic malignancies, 57 (20.4%) had rheumatologic diseases, and 98 (35.1%) were solid organ-transplant recipients. Anti–SARS-CoV-2 antibody levels increased in 74.9% of cases. Across the entire cohort, the median absolute antibody levels (expressed in AU/mL) increased from 7 (interquartile range (IQR), 0.1–69) to 243 (IQR, 2–4749) after the booster dose. The response significantly varied across subgroups: The transplant cohort showed the greatest increase in absolute antibody levels (from 52 (IQR, 7.25–184.5) to 1824 (IQR, 161–9686)), followed by the rheumatology (from 22 (IQR, 1–106) to 1291 (IQR, 6–6231)) and haemato-oncology (from 1 (IQR, 0.1–7) to 7.5 (IQR, 0.1–407.5)) cohorts. The χ² test was 8.30 for difference in fold change (p = 0.016). Of the 193 patients who were seronegative at baseline, 76 became seropositive after vaccination, corresponding to a 39.4% (95% CI, 32.8%–46.4%) seroconversion rate. Transplant patients had the highest seroconversion rate (58.3% (95% CI, 44.3%–71.2%)), followed by rheumatology (44.1% (95% CI, 28.9%–60.5%)) and haemato-oncology (29.7% (95% CI, 22%–38.8%); χ² = 11.87; p = 0.003) patients.DiscussionA third dose of BNT162b2 is immunogenic in most immunosuppressed individuals, although antibody response may differ based on the type of disease and immunosuppression. The antibody level that correlates with protection is still unknown; thus, future studies are needed to evaluate clinical outcomes.     

Longitudinal study comparing IgG antibodies induced by heterologous prime-boost COVID-19 vaccine

Vaccines are critical cost-effective tools to control the COVID-19 pandemic. The heterologous prime-boost vaccination has been used by many countries to overcome supply issues, so the effectiveness and safety of this strategy need to be better clarified. This study aims to verify the effect of heterologous prime-boost COVID-19 vaccination on healthcare professionals from Dante Pazzanese Hospital in Brazil. It was performed serological assays of vaccinated individuals after 2-dose of CoronaVac (Sinovac; n = 89) or ChAdOx1 nCoV-19 (Oxford-AstraZeneca; n = 166) followed by a BNT162b2 booster (Pfizer-BioNTech; n = 255). The serum antibodies anti-S (spike), anti-N (nucleocapsid), and anti-RBD (receptor binding domain) were assessed by enzyme-linked immunosorbent assay. The heterologous booster dose induced a 10-fold higher anti-Spike antibody regardless of the 2-dose of a prime vaccine. It was strikingly observed that BNT162b2 enhanced levels of anti-spike antibodies, even in those individuals who did not previously respond to the 2-dose of CoronaVac. In conclusion, the heterologous scheme of vaccination using mRNA as a booster vaccine efficiently enhanced the antibody response against SARS-CoV-2, especially benefiting those elderly who were seronegative with a virus-inactivated vaccine.     

Association between a low response to rubella vaccination and reduced anti-severe acute respiratory syndrome coronavirus 2 immune response after vaccination with BNT162b2: a cross-sectional study

ObjectivesSome vaccinated individuals fail to acquire an adequate immune response against infection. We aimed to determine whether mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination could induce a sufficient immune response against SARS-CoV-2 in low responders to other vaccinations.MethodsUsing data from health-care workers who received two doses of the BNT162b2 vaccine (BioNTech/Pfizer), we conducted a single-centre, cross-sectional study to determine whether low responders to measles, rubella, and hepatitis B virus (HBV) vaccinations could acquire sufficient antibodies after SARS-CoV-2 vaccination. From May 2021 to June 2021, participants were tested for anti-SARS-CoV-2 spike (anti-S) IgG antibodies at least 2 weeks after the second dose of BNT162b2. The association between a low response to measles, rubella, and HBV vaccinations and the post-vaccination anti-S IgG titre was evaluated using the multivariable linear regression analysis.ResultsAll 714 participants were positive for the anti-S IgG titre (≥50.0 AU/mL) after two doses of BNT162b2 (median, 7126.8 AU/mL; interquartile range, 4496.2–11 296.8). There were 323 (45.2%), 131 (18.3%), and 43 (6.0%) low responders to measles, rubella, and HBV vaccinations, respectively. In the multivariable linear regression analysis, low responders to rubella vaccination had significantly low acquisition of the anti-S IgG titre after two doses of the BNT162b2 vaccine (standardized coefficient β, ?0.110; 95% CI, ?0.175 to ?0.044).ConclusionsA low response to rubella vaccination is a potential predictor of a reduced response to SARS-CoV-2 vaccination. Further studies are needed to determine whether a low response to rubella vaccination is associated with the durability of SARS-CoV-2 vaccination-induced immune response.     

SARS-CoV-2 new infections among health-care workers after the first dose of the BNT162b2 mRNA COVID-19 vaccine. A hospital-wide cohort study

ObjectivesTo evaluate the effect of mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination on the incidence of new SARS-CoV-2 infections in health-care workers (HCW).MethodsThe evolution of the incident rate of microbiologically confirmed SARS-CoV-2 infection in a cohort of 2590 HCW after BNT162b2 mRNA SARS-CoV-2 vaccination, compared with the rate in the community (n = 170 513) was evaluated by mixed Poisson regression models.ResultsA total of 1820 HCW (70.3% of total) received the first dose of the BNT162b2 mRNA vaccine between 10 January and 16 January 2021, and 296 (11.4%) received it the following week. All of them completed vaccination 3 weeks later. Incidence rates of SARS-CoV-2 infection after the first dose of mRNA SARS-CoV-2 vaccine declined by 71% (Incidence Rate Ratio (IRR) 0.286, 95% CI 0.174–0.468; p < 0.001) and by 97% (IRR 0.03, 95% CI 0.013–0.068; p < 0.001) after the second dose, compared with the perivaccine time. SARS-CoV-2 incidence rates in the community (with a negligible vaccination rate) had a much lower decline: 2% (IRR 0.984, 95% CI 0.943–1.028; p 0.47) and 61% (IRR 0.390, 95% CI 0.375–0.406; p < 0.001) for equivalent periods. Adjusting for the decline in the community, the reduction in the incident rates among HCW were 73% (IRR 0.272, 95% CI 0.164–0.451 p < 0.001) after the first dose of the vaccine and 92% (IRR 0.176, 95% CI 0.033–0.174; p < 0.001) after the second dose.ConclusionsmRNA SARS-CoV-2 vaccination is associated with a dramatic decline in new SARS-CoV-2 infection among HCW, even before the administration of the second dose of the vaccine.     

Association between IgG antibody levels and adverse events after first and second Bnt162b2 mRNA vaccine doses

ObjectivesThis study sought to correlate the SARS-CoV-2 IgG antibody response level to the BNT162b2 (Pfizer BioNTech) mRNA vaccine after the first and second doses with the reported adverse events.MethodsThis cohort study examined the adverse events profiles of people vaccinated with BNT162b2 in our institute between late 2020 and May 2021. Adverse events, age, and sex were reported using an electronic questionnaire, and their SARS-CoV-2 IgG antibody levels were retrieved from the hospital database.ResultsBetween 20 December 2020 and 31 May 2021, the adverse events questionnaire was completed by 9700 individuals who received the first vaccine dose and 8321 who received the second dose. After the first and second doses, the average antibody levels were 62.34 AU/mL (mean 4–373) and 188.19 AU/mL (mean 20–392), respectively. All of the adverse events, except local pain, were more common after the second vaccine dose. Multivariate analysis showed that after the first vaccine dose, female sex and younger age (but not IgG titres) were associated with a higher probability of adverse events (OR 2.377, 95% CI, 1.607–3.515, p = 0.000; OR 0.959, 95% CI, 0.944–0.977, p £0.000; OR 1.002, 95% CI, 0.995–1.008, p £0.601; respectively); however, all three parameters were associated with the incidence of adverse events after the second dose (OR 2.332, 95% CI, 1.636–3.322, p = 0.000; OR 0.984, 95% CI, 0.970–0.999, p £0.039; OR 1.004, 95% CI, 1.001–1.007, p £0.022; respectively).DiscussionAdverse events are significantly more common after the second BNT162b2 vaccine dose than after the first dose. We found an association between sex, age, and SARS-CoV-2 IgG antibody titre with the incidence of adverse events.     

Antibody responses to BNT162b2 mRNA COVID-19 vaccine and their predictors among healthcare workers in a tertiary referral hospital in Japan

ObjectivesThis study aimed to determine antibody responses in healthcare workers who receive the BNT162b2 mRNA COVID-19 vaccine and identify factors that predict the response.MethodsWe recruited healthcare workers receiving the BNT162b2 mRNA COVID-19 vaccine at the Chiba University Hospital COVID-19 Vaccine Center. Blood samples were obtained before the 1st dose and after the 2nd dose vaccination, and serum antibody titers were determined using Elecsys® Anti-SARS-CoV-2S, an electrochemiluminescence immunoassay. We established a model to identify the baseline factors predicting post-vaccine antibody titers using univariate and multivariate linear regression analyses.ResultsTwo thousand fifteen individuals (median age 37-year-old, 64.3% female) were enrolled in this study, of which 10 had a history of COVID-19. Before vaccination, 21 participants (1.1%) had a detectable antibody titer (≥0.4 U/mL) with a median titer of 35.9 U/mL (interquartile range [IQR] 7.8 – 65.7). After vaccination, serum anti-SARS-CoV-2S antibodies (≥0.4 U/mL) were detected in all 1774 participants who received the 2nd dose with a median titer of 2060.0 U/mL (IQR 1250.0 – 2650.0). Immunosuppressive medication (p < 0.001), age (p < 0.001), time from 2nd dose to sample collection (p < 0.001), glucocorticoids (p = 0.020), and drinking alcohol (p = 0.037) were identified as factors predicting lower antibody titers after vaccination, whereas previous COVID-19 (p < 0.001), female (p < 0.001), time between 2 doses (p < 0.001), and medication for allergy (p = 0.024) were identified as factors predicting higher serum antibody titers.ConclusionsOur data demonstrate that healthcare workers universally have good antibody responses to the BNT162b2 mRNA COVID-19 vaccine. The predictive factors identified in our study may help optimize the vaccination strategy.     

Real-world safety data for the Pfizer BNT162b2 SARS-CoV-2 vaccine: historical cohort study

ObjectiveThe Pfizer BNT162b2 vaccine showed a reassuring safety profile in clinical trials, but real-world data are scarce. Bell's palsy, herpes zoster, Guillain–Barré syndrome (GBS) and other neurological complaints in proximity to vaccination have received special public attention. We compared their rates among vaccinated and unvaccinated individuals.MethodsIndividuals ≥16 years vaccinated with at least one dose of BNT162b2 were eligible for this historical cohort study in a health maintenance organization insuring 1.2 million citizens. Each vaccinee was matched to a non-vaccinated control by sex, age, population sector (general Jewish, Arab, ultra-orthodox Jewish) and comorbidities. Diagnosis of Covid-19 before or after vaccination was an exclusion criterion. The outcome was a diagnosis of Bell's palsy, GBS, herpes zoster or symptoms of numbness or tingling, coded in the visit diagnosis field using ICD-9 codes. Diagnoses of Bell's palsy and GBS were verified by individual file review.ResultsOf 406 148 individuals vaccinated during the study period, 394 609 (97.2%) were eligible (11 539 excluded). A total of 233 159 (59.1%) were matched with unvaccinated controls. Mean follow was 43 ± 15.14 days. In vaccinated and unvaccinated individuals there were 23 versus 24 cases of Bell's palsy (RR 0.96, CI 0.54–1.70), one versus zero cases of GBS, 151 versus 141 cases of herpes zoster (RR 1.07, CI 0.85–1.35) and 605 versus 497 cases of numbness or tingling (RR 1.22, CI 1.08–1.37), respectively.DiscussionNo association was found between vaccination, Bell's palsy, herpes zoster or GBS. Symptoms of numbness or tingling were more common among vaccinees. This study adds reassuring data regarding the safety of the BNT162b2 vaccine.     

Adverse Events in Healthcare Workers after the First Dose of ChAdOx1 nCoV-19 or BNT162b2 mRNA COVID-19 Vaccination: a Single Center Experience

Coronavirus disease 2019 vaccinations for healthcare workers (HCWs) have begun in South Korea. To investigate adverse events (AEs) of the first dose of each vaccine, any symptom was collected daily for seven days after vaccination in a tertiary hospital. We found that 1,301 of 1,403 ChAdOx1 nCoV-19 recipients and 38 of 80 BNT162b2 recipients reported AEs respectively (90.9% vs. 52.5%): injection-site pain (77.7% vs. 51.2%), myalgia (60.5% vs. 11.2%), fatigue (50.7% vs. 7.5%), headache (47.4% vs. 7.5%), and fever (36.1% vs. 5%; P < 0.001 for all). Young HCWs reported more AEs with ChAdOx1 nCoV-19 than with BNT162b2. No incidences of anaphylaxis were observed. Only one serious AE required hospitalization for serious vomiting, and completely recovered. In conclusion, reported AEs were more common in recipients with ChAdOx1 nCoV-19 than in those with BNT162b2. However, most of the reported AEs were mild to moderate in severity. Sufficient explanation and preparation for expected AEs required to promote widespread vaccination.     

Risk of myocarditis and pericarditis following coronavirus disease 2019 messenger RNA Vaccination—A nationwide study

BackgroundAn extended interval between the two primary doses may reduce the risk of myocarditis/pericarditis after COVID-19 mRNA vaccination. Taiwan has implemented a two-dose regimen with a 12-week interval for adolescents. Here we present nationwide data of myocarditis/pericarditis following COVID-19 vaccinations.MethodsData on adverse events of myocarditis/pericarditis were from the Taiwan Vaccine Adverse Events Reporting System between March 22, 2021, and February 9, 2022. The reporting rates according to sex, age, and vaccine type were calculated. We investigated the rates among young individuals under different two-dose intervals and among those who received two doses of different vaccines.ResultsAmong 204 cases who met the case definition of myocarditis/pericarditis, 75 cases occurred after the first dose and 129 after the second. The rate of myocarditis/pericarditis after COVID-19 vaccination varied across sex and age groups and was highest after the second dose in males aged 12–17 years (126.79 cases per million vaccinees) for the BNT162b2 vaccine and in males aged 18–24 years (93.84 cases per million vaccinees) for the mRNA-1273 vaccine. The data did not suggest an association between longer between-dose interval and lower rate of myocarditis/pericarditis among males and females aged 18–24 or 25–29 years who received two doses of the BNT162b2 or mRNA-1273 vaccine. Rates of myocarditis/pericarditis in males and females aged 18–49 years after receiving ChAdOx1-S - mRNA-1273 vaccination was significantly higher than after ChAdOx1-S - ChAdOx1-S vaccination.ConclusionsMyocarditis and pericarditis are rare following mRNA vaccination, with higher risk occurring in young males after the second dose.     

Neutralizing antibody activity against the B.1.617.2 (delta) variant 8 months after two-dose vaccination with BNT162b2 in health care workers

ObjectivesHumoral immunity wanes over time after two-dose BNT162b2 vaccination. Emerging variants of concern, such as the B.1.617.2 (delta) variant, are increasingly responsible for breakthrough infections owing to their higher transmissibility and partial immune escape. Longitudinal data on neutralization against the B.1.617.2 (delta) variant are urgently needed to guide vaccination strategies.MethodsIn this prospective longitudinal observational study, anti-S1 IgG and surrogate neutralizing antibodies were measured in 234 collected samples from 60 health care workers after two-dose vaccination with BNT162b2 at five different time points over an 8-month period. In addition, antibodies against various severe acute respiratory syndrome coronavirus 2 epitopes, neutralization against wild-type, and cross-neutralization against the B.1.617.2 (delta) variant using a live virus assay were measured 6 weeks (second time point) and 8 months (last time point) after first vaccine dose.ResultsMedian (interquartile range) anti-S1 IgG, surrogate neutralizing, and receptor-binding domain antibodies decreased significantly from a maximum level of 147 (102–298), 97 (96–98), and 20 159 (19 023–21 628) to 8 (4–13), 92 (80–96), and 15 324 (13 055–17 288) at the 8-month follow-up, respectively (p < 0.001 for all). Neutralization against the B.1.617.2 (delta) variant was detectable in all 36 (100%) participants at 6 weeks and in 50 of 53 (94%) participants 8 months after first vaccine dose. Median (interquartile) ID₅₀ as determined by a live virus assay decreased from 160 (80–320) to 40 (20–40) (p < 0.001).DiscussionAlthough humoral immunity wanes over time after two-dose BNT162b2 vaccination in healthy individuals, most individuals still had detectable neutralizing activity against the B.1.617.2 (delta) variant after 8 months.     

Effectiveness of mRNA-BNT162b2, mRNA-1273, and ChAdOx1 nCoV-19 vaccines against COVID-19 in healthcare workers: an observational study using surveillance data

ObjectivesHealthcare workers (HCWs) at increased risk of coronavirus disease 2019 (COVID-19) were among the primary targets for vaccine campaigns. We aimed to estimate the protective efficacy of the first three COVID-19 vaccines available in Western Europe.MethodsWe merged two prospective databases that systematically recorded, in our institution: (a) HCWs positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by RT-PCR on nasopharyngeal samples, and (b) HCWs who received at least one dose of COVID-19 vaccine. We excluded HCWs with SARS-CoV-2 infection during the 6 months prior to the study. HCWs were categorized as non-vaccinated if they received no vaccine and until the first injection +13 days, partially vaccinated from the first injection +14 days to the second injection +13 days, and fully vaccinated thereafter.ResultsOf the 8165 HCWs employed in our institution, 360 (4.4%) tested positive for SARS-CoV-2 by RT-PCR during the study period (4th January to 17th May 2021). Incidence was 9.1% (8.2–10.0) in non-vaccinated HCWs, 1.2% (0.7–1.9) after one dose of ChAdOx1 nCoV-19, 1.4% (0.6–2.3) and 0.5% (0.1–1.0) after one and two doses of mRNA BNT162b2, 0.7% (0.1–1.9) and 0% after one and two doses of mRNA-1273 (p < 0.0001). Vaccine effectiveness (Cox model) was estimated at, respectively, 86.2% (76.5–91.0), 38.2% (6.3–59.2), and 49.2% (19.1–68.1) 14 days after the first dose for ChAdOx1 nCoV-19, mRNA-1273, and mRNA-BNT162b2, and 100% (ND) and 94.6% (61.0–99.2) 14 days after the second dose for mRNA-1273 and mRNA-BNT162b2.ConclusionsIn this real-world study, the observed effectiveness of COVID-19 vaccines in HCWs was in line with the efficacy reported in pivotal randomized trials.     

Antibody response to SARS-CoV-2 mRNA vaccine among kidney transplant recipients: a prospective cohort study

ObjectivesWe aimed to evaluate the rates of antibody response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine among kidney transplant recipients, and to identify factors associated with reduced immunogenicity.MethodsThis was a prospective cohort study including consecutive kidney transplant recipients in a single referral transplant centre. Participants were tested for anti-spike (anti-S) antibodies 2–4 weeks after a second vaccine dose. Primary outcome was rate of seropositivity. Univariate and multivariate analyses were conducted to identify factors associated with seropositivity.ResultsOf 308 kidney transplant recipients included, only 112 (36.4%) tested positive for anti-S antibodies 2–4 weeks after receiving the second dose of BNT162b2 vaccine. Median antibody titre was 15.5 AU/mL (interquartile range (IQR) 3.5–163.6). Factors associated with antibody response were higher estimated glomerular filtration rate (eGFR) (odds ratio (OR) 1.025 per mL/min/1.73 m², 95% confidence interval (CI) 1.014–1.037, p < 0.001), lower mycophenolic acid dose (OR 2.347 per 360 mg decrease, 95%CI 1.782–3.089, p < 0.001), younger age (OR 1.032 per year decrease, 95%CI 1.015–1.05, p < 0.001) and lower calcineurin inhibitor (CNI) blood level (OR 1.987, 95%CI 1.146–3.443, p 0.014). No serious adverse events resulting from the vaccine were reported.ConclusionsKidney transplant recipients demonstrated an inadequate antibody response to SARS-CoV-2 mRNA vaccination. Immunosuppression level was a significant factor in this response. Strategies to improve immunogenicity should be examined in future studies.