Kinetics of dried blood spot-measured anti-SARS-CoV2 Spike IgG in mRNA-vaccinated healthcare workers

Abstract

IntroductionOne of the major criticisms facing the research community during SARS-CoV2 pandemic was the lack of large-scale, longitudinal data on the efficacy of the SARS-CoV2 mRNA vaccines. Currently, even if COVID-19 antiviral treatments have been authorized by European Medicine Agency, prevention through approved specific vaccines is the best approach available in order to contain the ongoing pandemic.ObjectivesHere, we studied the antibody kinetic over a one-year period from vaccination with the Pfizer-BioNTech (Pfizer) vaccines and subsequent boosting with either the BioNTech or Moderna (Spikevax) vaccines in a large cohort of 8,071 healthcare workers (HCW). We also described the impact of SARS-CoV2 infection on antibody kinetic over the same period.MethodsWe assessed the anti SARS-CoV2 Spike IgG antibody kinetic by the high throughput dried blood spot (DBS) collection method and the GSP®/DELFIA® Anti-SARS-CoV2 IgG assay (PerkinElmer®).ResultsOur data support existing models showing that SARS-CoV2 vaccination elicits strong initial antibodies responses that decline with time but are transitorily increased by administering a vaccine booster. We also showed that using heterologous vaccine/booster combinations a stronger antibody response was elicited than utilizing a booster from the same vaccine manufacturer. Furthermore, by considering the impact of SARS-CoV2 infection occurrence in proximity to the scheduled booster administration, we confirmed that booster dose did not contribute significantly to elicit higher antibody responses.ConclusionDBS sampling in our large population of HCWs was fundamental to collect a large number of specimens and to clarify the effective mRNA vaccine-induced antibody kinetic and the role of both heterologous boosters and SARS-CoV2 infection in modulating antibody responses.

Vaccination, time lost from work, and COVID-19 infections: a Canadian healthcare worker retrospective cohort study

“…Booster doses have been recommended to HCWs with the expectation that it will maintain the benefits of vaccination and reduce absenteeism. Some studies have shown booster doses inducing a significant and sustained increase in anti-SP IgG titers ( 18 ) while others have found a more short-lived impact ( 19 ). Nonetheless, there is a growing body of evidence on the side effects of COVID-19 vaccines and resulting time off work ( 20–22 ), which should not be ignored.…”