Investigation of the Neutralizing Antibody Response of Healthcare Workers at a Korean University Hospital Six Months After the Introduction of the COVID-19 Vaccine

Longitudinal Analysis of SARS-CoV-2-Specific Cellular and Humoral Immune Responses and Breakthrough Infection following BNT162b2/BNT162b2/BNT162b2 and ChAdOx1/ChAdOx1/BNT162b2 Vaccination: A Prospective Cohort in Naive Healthcare Workers

“…Humoral immune response, measured by total binding antibody and neutralizing activity, also reached its peak level at 1-2 months following the second or third vaccination and then declined rapidly over the 6-month period post-vaccination. The decline in humoral immunity was observed in both vaccine groups, but the ChAd group exhibited a faster decrease in both binding and neutralizing antibody levels, which aligns with findings from a previous study [22]. Additionally, when comparing humoral responses between the two groups, the BNT group tended to have a higher humoral response than the ChAd group at all sampling points.…”

Immune Responses After Vaccination With Primary 2-Dose ChAdOx1 Plus a Booster of BNT162b2 or Vaccination With Primary 2-Dose BNT162b2 Plus a Booster of BNT162b2 and the Occurrence of Omicron Breakthrough Infection

“…In a few studies, including this study, the neutralizing response was lower in the ChAdOx1/ChAdOx1 group than in the BNT162b2/BNT162b2 group. 3 11 Additionally, three large cohort studies conducted in the United Kingdom (UK) directly compared the protective efficacy against COVID-19 between the ChAdOx1/ChAdOx1 and BNT162b2/BNT162b2 groups. 12 13 14 Although there was no difference in COVID-19 incidence or hospitalization between the two groups in a previous study, 11 the ChAdOx1/ChAdOx1 group had a greater COVID-19 incidence and hospitalization rate than that of the BNT162b2/BNT162b2 group in other studies.…”

“… 1 Healthcare workers (HCWs) were one of the first groups to receive the COVID-19 vaccine due to the risk of occupational exposure to SARS-CoV-2 2 ; specifically, they underwent two types of primary vaccination series: a two-dose BNT162b2 (Pfizer-BioNTech) series and a two-dose ChAdOx1 nCoV-19 (Oxford-AstraZeneca; referred to as AZD1222) series. 3 From October 2021, the booster vaccination was administered to the majority of HCWs after having previously received one of the mRNA vaccines, namely BNT162b2. In Korea, there were two major vaccination groups in HCWs—the ChAdOx1/ChAdOx1/BNT162b2 (CCB) and the BNT162b2/BNT162b2/BNT162b2 (BBB) group.…”

New Insights Into SARS-CoV-2-specific Antibody Levels in Kidney Transplantation Recipients After Three Vaccination Doses

“…During the early stages of the pandemic, studies suggested an association between humoral immune markers, such as SARS-CoV-2-specific binding and neutralizing antibodies, and symptomatic infections and disease severity [4][5][6][7][8][9][10]. However, studies examining the correlation between antibody levels and clinical courses have produced inconsistent results [11][12][13], complicating the utilization of SARS-CoV-2-specific antibody titers in aiding medical decision-making.…”

“…However, their statistical analyses indicated that the relationship between antibody titers and breakthrough infections is not linear; instead, it appears to be characterized by a distinct threshold. Antibody levels associated with an increased risk of breakthrough infection have displayed variations across studies [9][10][11][12][13][14][15][16][17]. The authors proposed several factors that could account for this variability, including disparities in test kits (including the use of non-standardized antibody units), varying levels of patient immunosuppression resulting from diverse drug regimens among hospitals, variations in exposure and viral loads from different sources, differences in healthcare facilities, and variances in the prevalence of Omicron infection within the community.…”