Abstract
To mitigate the massive COVID-19 burden caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), several vaccination campaigns were initiated. We performed a single-center observational trial to monitor the mid- (3 months) and long-term (10 months) adaptive immune response and to document breakthrough infections (BTI) in healthcare workers ( n = 84) upon BNT162b2 vaccination in a real-world setting. Firstly, serology was determined through immunoassays. Secondly, antibody functionality was analyzed via in vitro binding inhibition and pseudovirus neutralization and circulating receptor-binding domain (RBD)-specific B cells were assessed. Moreover, the induction of SARS-CoV-2-specific T cells was investigated by an interferon-γ release assay combined with flowcytometric profiling of activated CD4 + and CD8 + T cells. Within individuals that did not experience BTI ( n = 62), vaccine-induced humoral and cellular immune responses were not correlated. Interestingly, waning over time was more pronounced within humoral compared to cellular immunity. In particular, 45 of these 62 subjects no longer displayed functional neutralization against the delta variant of concern (VoC) at long-term follow-up. Noteworthily, we reported a high incidence of symptomatic BTI cases (17.11%) caused by alpha and delta VoCs, although vaccine-induced immunity was only slightly reduced compared to subjects without BTI at mid-term follow-up.
Keywords: BNT162b2 vaccine; SARS-CoV-2; breakthrough infection; healthcare workers; long-term monitoring; variants of concern.
【저자키워드】 SARS-CoV-2, BNT162b2 vaccine, Healthcare workers, variants of concern, Long-term monitoring, Breakthrough infection, 【초록키워드】 COVID-19, BNT162b2 vaccine, coronavirus, vaccination, Healthcare workers, Trial, serology, antibody, Cellular immune response, T cells, neutralization, variant, B cells, variants of concern, interferon, in vitro, severe acute respiratory syndrome Coronavirus, delta variant, CD4, CD8, variants, healthcare worker, B cell, BNT162b2, immunoassays, cellular immunity, pseudovirus, symptomatic, immune responses, healthcare, Alpha, breakthrough infections, Breakthrough infection, Follow-up, incidence, Adaptive immune response, respiratory, SARS-CoV-2-specific T cells, binding, Vaccine-induced immunity, Long-term follow-up, humoral, interferon-γ, acute respiratory syndrome, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, subject, individual, domain, single-center, circulating, MONITOR, delta VoCs, mitigate, analyzed, performed, caused, reported, investigated, reduced, functional, activated, was determined, initiated, not correlated, SARS-CoV-2-specific T cell, were assessed, 【제목키워드】 concern, Belgium, induced, residual,