Incidencia y factores asociados con las reacciones adversas tras la primera dosis de la vacuna Pfizer-BioNTech en trabajadores de la salud.

OBJECTIVE: To determine the incidence of adverse reactions (AR) after the first dose of Pfizer-BioNTech vaccine, and to identify some factors associated with AR. METHOD: A retrospective cohort study was conducted. Data were obtained through an epidemiological survey answered online. Multivariate analyses were performed to identify factors associated with early (< 2 h) and late (≥ 2 h) AR. RESULTS: A total of 2295 health care workers were included; in them, the cumulative incidence of AR was 18.2% (95% confidence interval: 16.6-19.8), where the majority were late (78.2%). The associated factors that increased the risk of early AR were being female (odds ratio [OR]: 2.23, p = 0.002) and belonging to the medical staff (OR: 1.56; p = 0.041). In late AR were being female (OR: 1.94; p < 0.0001); on the other hand, diabetes (OR: 0.46; p = 0.021), asthma (OR: 0.53; p = 0.040) and smoking (OR: 0.44, p = 0.002) were inversely associated factors. Interestingly, history of COVID-19 was not associated with either early or late AR. CONCLUSIONS: The risk of presenting some type of AR due to the Pfizer-BioNTech vaccine in health care workers is < 20%.

OBJETIVO: Determinar la incidencia de reacciones adversas (RA) tras la primera dosis de la vacuna Pfizer-BioNTech e identificar algunos factores asociados con ellas. MÉTODO: Se realizó un estudio de cohorte retrospectiva. Los datos fueron obtenidos mediante una encuesta epidemiológica contestada en línea. Se realizaron análisis multivariados para identificar factores asociados con las RA tempranas (< 2 h) y tardías (≥ 2 h). RESULTADOS: Se incluyeron 2295 trabajadores de la salud; en ellos, la incidencia acumulada de RA fue del 18.2% (intervalo de confianza del 95%: 16.6-19.8%) y la mayoría fueron tardías (78.2%). Las RA tempranas más frecuentes fueron dolor local, cefalea y mareo; en las tardías fueron dolor local, cefalea y fatiga. No se documentaron casos de anafilaxia; sin embargo, en el grupo de RA tempranas y tardías hubo un caso y tres casos, respectivamente, con síntomas sistémicos que afectaron a dos órganos diferentes. Los factores asociados que incrementaron el riesgo de RA tempranas fueron ser mujer (odds ratio [OR]: 2.23; p = 0.002) y pertenecer al personal médico (OR: 1.56; p = 0.041). En las RA tardías fue ser mujer (OR: 1.94; p < 0.0001); por su parte, la diabetes (OR: 0.46; p = 0.021), el asma (OR: 0.53; p = 0.040) y el tabaquismo (OR: 0.44; p = 0.002) fueron factores asociados inversamente. Es interesante que la historia de COVID-19 no se asoció con RA tempranas ni tardías. CONCLUSIONES: El riesgo de presentar algún tipo de RA debido a la vacuna Pfizer-BioNTech en trabajadores de la salud es < 20%.

Immunogenicity, effectiveness and safety of COVID-19 vaccine in older adults living in nursing homes: A real-life study.

INTRODUCTION: BNT162b2 (BioNTech and Pfizer) is a nucleoside-modified mRNA vaccine that provides protection against SARS-CoV-2 infection and is generally well tolerated. However, data about its efficacy, immunogenicity and safety in people of old age or with underlying chronic conditions are scarce. PURPOSE: To describe BNT162b2 (BioNTech and Pfizer) COVID-19 vaccine immunogenicity, effectiveness and reactogenicity after complete vaccination (two doses), and immunogenicity and reactogenicity after one booster, in elders residing in nursing homes (NH) and healthy NH workers in real-life conditions. METHODS: Observational, ambispective, multicenter study. Older adults and health workers were recruited from three nursing homes of a private hospital corporation located in three Spanish cities. The primary vaccination was carried out between January and March 2021. The follow-up was 13 months. Humoral immunity, adverse events, SARS-CoV-2 infections, hospitalizations and deaths were evaluated. Cellular immunity was assessed in a participant subset. RESULTS: A total of 181 residents (mean age 84.1 years; 89.9% females, Charlson index ≥2: 45%) and 148 members of staff (mean age 45.2 years; 70.2% females) were surveyed (n:329). After primary vaccination of 327 participants, vaccine response in both groups was similar; ≈70% of participants, regardless of the group, had an antibody titer above the cut-off considered currently protective (260BAU/ml). This proportion increased significantly to ≈ 98% after the booster (p<0.0001 in both groups). Immunogenicity was largely determined by a prior history of COVID-19 infection. Twenty residents and 3 workers were tested for cellular immunity. There was evidence of cellular immunity after primary vaccination and after booster. During the study, one resident was hospitalized for SARS-CoV-2. No SARS-CoV-2-related deaths were reported and most adverse events were mild. CONCLUSIONS: Our results suggest that the BNT162b2 mRNA COVID-19 vaccine is immunogenic, effective and safe in elderly NH residents with underlying chronic conditions.

Commercialized kits to assess T-cell responses against SARS-CoV-2 S peptides. A pilot study in health care workers.

BACKGROUND: It is crucial to assess the levels of protection generated by natural infection or SARS-CoV-2 vaccines, mainly in individuals professionally exposed and in vulnerable groups. Measuring T-cell responses may complement antibody tests currently in use as correlates of protection. Our aim was to assess the feasibility of a validated assay of T-cell responses. METHODS: Twenty health-care-workers (HCW) were included. Antibody test to SARS-CoV-2 N and S-proteins in parallel with a commercially available whole-blood-interferon-gamma-release-assay (IGRA) to S-peptides and two detection methods, CLIA and ELISA were determined. RESULTS: IGRA test detected T-cell responses in naturally exposed and vaccinated HCW already after first vaccination dose. The correlation by the two detection methods was very high (R>0.8) and sensitivity and specificity ranged between 100 and 86% and 100-73% respectively. Even though there was a very high concordance between specific antibody levels and the IGRA assay in the ability to detect immune response to SARS-CoV-2, there was a relatively low quantitative correlation. In the small group primed by natural infection, one vaccine dose was sufficient to reach immune response plateau. IGRA was positive in one, with Ig(S) antibody negative vaccinated immunosuppressed HCW illustrating another advantage of the IGRA-test. CONCLUSION: Whole-blood-IGRA-tests amenable to automation and constitutes a promising additional tool for measuring the state of the immune response to SARS-CoV-2; they are applicable to large number of samples and may become a valuable correlate of protection to COVID-19, particularly for vulnerable groups at risk of being re-exposed to infection, as are health-care-workers.