Post-vaccination SARS-CoV-2 infections and incidence of presumptive B.1.427/B.1.429 variant among healthcare personnel at a northern California academic medical center. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America Jacobson, K. B., Pinsky, B. A., Montez Rath, M. E., Wang, H., Miller, J. A., Skhiri, M., Shepard, J., Mathew, R., Lee, G., Bohman, B., Parsonnet, J., Holubar, M. 2021

Abstract

BACKGROUND: Although mRNA-based SARS-CoV-2 vaccines report =90% efficacy, breakthrough infections occur. Little is known about the effectiveness of these vaccines against SARS-CoV-2 variants, including the highly-prevalent B.1.427/B.1.429 variant in California..METHODS: In this quality improvement project, we collected demographic and clinical information from post-vaccine SARS-CoV-2 cases (PVSCs), defined as health care personnel (HCP) with positive SARS-CoV-2 NAAT after receiving =1 vaccine dose. Available specimens were tested for L452R, N501Y and E484K mutations by RT-PCR. Mutation prevalence was compared among unvaccinated, early post-vaccinated (<=14 days after dose 1), partially vaccinated (positive test >14 days after dose 1 and =14 days after dose 2) and fully vaccinated (>14 days after dose 2) PVSCs.RESULTS: From December 2020-April 2021, >=23,090 HCPS received at least1 dose of an mRNA-based SARS-CoV-2 vaccine, and 660 HCP cases of SARS-CoV-2 occurred of which 189 were PVSCs. Among the PVSCs, 114 (60.3%), 49 (25.9%) and 26 (13.8%) were early post-vaccination, partially vaccinated, and fully vaccinated, respectively. Of 261 available samples from vaccinated and unvaccinated HCP, 103 (39.5%), including 42 PVSCs (36.5%), had L452R mutation presumed to be B.1.427/B.1.429,. When adjusted for community prevalence of B.1.427/B.1.429, PVSCs did not have significantly elevated risk for infection with B.1.427/B.1.429 compared with unvaccinated HCP.CONCLUSIONS: Most PVSCs occurred prior to expected onset of full, vaccine-derived immunity. Presumptive B.1.427/B.1.429 was not more prevalent in post-vaccine cases than in unvaccinated SARS-CoV-2 HCP. Continued infection control measures, particularly =14 days post-vaccination, and continued variant surveillance in PVSCs is imperative to control future SARS-CoV-2 surges.

View details for DOI 10.1093/cid/ciab554

View details for PubMedID 34137815