Broad immunogenicity to prior SARS-CoV-2 strains and JN.1 variant elicited by XBB.1.5 vaccination in nursing home residents.

Background: SARS-CoV-2 vaccination has reduced hospitalization and mortality for nursing home residents (NHRs). However, emerging variants coupled with waning immunity, immunosenescence, and variability of vaccine efficacy undermine vaccine effectiveness. We therefore need to update our understanding of the immunogenicity of the most recent XBB.

Second monovalent SARS-CoV-2 mRNA booster restores Omicron-specific neutralizing activity in both nursing home residents and health care workers.

We examined whether the second monovalent SARS-CoV-2 mRNA booster increased antibody levels and their neutralizing activity to Omicron variants in nursing home residents (NH) residents and healthcare workers (HCW). We sampled 376 NH residents and 63 HCW after primary mRNA vaccination, first and second boosters, for antibody response and pseudovirus neutralization assay against SARS-CoV-2 wild-type (WT) (Wuhan-Hu-1) strain, Omicron BA.1 and BA.