Durability and breadth of neutralisation following multiple antigen exposures to SARS-CoV-2 infection and/or COVID-19 vaccination.

Background: Given the importance of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the prevention of severe coronavirus disease 2019 (COVID-19), detailed long-term analyses of neutralising antibody responses are required to inform immunisation strategies.

Methods: In this study, longitudinal neutralising antibody titres to an ancestral SARS-CoV-2 isolate and cross-neutralisation to delta and omicron isolates were analysed in individuals previously infected with SARS-CoV-2, vaccinated against COVID-19, or a complex mix thereof with up to two years of follow-up.

Findings: Both infection-induced and vaccine-induced neutralising responses against SARS-CoV-2 appeared to follow similar decay patterns.

Analysis of Neutralization Titers against SARS-CoV-2 in Health-Care Workers Vaccinated with Prime-Boost mRNA-mRNA or Vector-mRNA COVID-19 Vaccines.

With increasing numbers of vaccine-breakthrough infections worldwide, assessing the immunogenicity of vaccinated health-care workers that are frequently exposed to SARS-CoV-2-infected individuals is important. In this study, neutralization titers against SARS-CoV-2 were assessed one month after completed prime-boost vaccine regimens in health-care workers vaccinated with either mRNA-mRNA (Comirnaty, BioNTech-Pfzier, Mainz, Germany/New York, NY, USA, = 98) or vector-based (Vaxzevria, Oxford-AstraZeneca, Cambridge, UK) followed by mRNA-based (Comirnaty or Spikevax, Moderna, Cambridge, MA, USA) vaccines ( = 16). Vaccine-induced neutralization titers were compared to time-matched, unvaccinated individuals that were infected with SARS-CoV-2 and presented with mild symptoms ( = 38).