Humoral and Cellular Response and Associated Variables Nine Months following BNT162b2 Vaccination in Healthcare Workers

Abstract

In this study, we aimed to illustrate the trajectory of humoral and cellular immunity nine months after primary vaccination with the BNT162b2 mRNA vaccine among 189 healthcare workers (HCWs). Additionally, we endeavored to identify correlations between immunity parameters and a number of common variables and comorbidities. A total of 189 healthcare workers (HCWs), vaccinated against COVID-19, were finally included in the study. All of the subjects had received two doses of the BNT162b2 vaccine; had undergone antibody tests one, four and nine months post-vaccination; and had completed a medical questionnaire. Further samples taken at nine months were tested for cellular immunity. No participants had evidence of COVID-19 infection pre- or post-vaccination. An anti-S1 receptor binding domain (RBD) antibody assay was used to assess humoral response, and cellular immunity was estimated with an INF-γ release assay (IGRA). Statistical analysis was performed using STATA. We report a statistically significant antibody drop over time. Being above the age of 40 or a smoker reduces the rise of antibodies by 37% and 28%, respectively. More than half of the participants did not demonstrate T-cell activation at nine months. Female gender and antibody levels at four months predispose detection of cellular immunity at nine months post-immunization. This study furthers the qualitative, quantitative, and temporal understanding of the immune response to the BNT162b2 mRNA vaccine and the effect of correlated factors.

Long‐term dynamics of natural killer cells in response to SARS‐CoV‐2 vaccination: Persistently enhanced activity postvaccination

“…Spike‐specific IgG were significantly increased at all timepoints when compared with T0. Consistent with existing data in the field, 29–31 Spike specific IgG were significantly decreased at T3 compared with T2, thus confirming the finding of reduced humoral immunity months after vaccination (Figure ). Neutralizing antibodies (NAb) activity was undetectable in all subjects at baseline (inhibition <20%).…”

Cellular Immunity of SARS-CoV-2 in the Borriana COVID-19 Cohort: A Nested Case–Control Study

“…However, in nursing home residents, the rate and frequency of detectable SARS-CoV-2 IFN-γ–T-cell responses after vaccination was lower than in controls in Spain [ 54 ], and in England, residents of long-term care facilities presented with lower T cell response with higher age [ 82 ]. In Greece, in a cohort of healthcare workers, females had a higher T cell response [ 83 ]. In Ireland, Townsend and co-authors [ 84 ], in a cohort of COVID-19 patients and non-infected controls, reported that activated CD4+ and CD8+ T cell responses increased with age, but no association with sex was found.…”

Prolonged SARS-CoV-2 T Cell Responses in a Vaccinated COVID-19-Naive Population

“…A prospective observational study conducted with healthcare workers demonstrated a notable decrease in both humoral and cellular immune responses between 4 and 7 months following complete vaccination, in contrast to the decline observed between 3 and 4 months [ 29 ]. Moreover, it was recently demonstrated that more than half of the SARS-CoV-2-naive vaccines had lost their cellular immunity nine months post-vaccination [ 30 ]. In young SARS-CoV-2-naive adults particularly, T cell responses were not correlated with peak antibody titers that remained high even six months after vaccination, with a gradual decline [ 31 ].…”