One-dose Vaxzevria highly effective in Beta and Delta variants

Results from the Canadian Immunization Research Network (CIRN) with support from Public Health Agency of Canada and the Canadian Institutes of Health Research, published as a pre-print, demonstrated one dose of Vaxzevria was 82% effective against hospitalization or death caused by the Beta/Gamma variants of the SARS-CoV-2 virus.

AstraZeneca’s (LSE: AZN) COVID-19 vaccine also showed a high level of effectiveness against the Delta (B.617.2, ‘Indian’) and Alpha (B.1.1.7, ‘Kent’) variants with an 87% and 90% reduction of hospitalizations or deaths respectively. The effectiveness of Vaxzevria after one dose against hospitalization or death was similar to that of other vaccines tested in the study. Follow-up time was not sufficient to report on effectiveness of Vaxzevria after two doses, other studies have shown an increased effectiveness following the indicated two-dose schedule.

Vaxzevria was effective against milder symptomatic disease although, given that data was only reported after a first dose instead of the indicated two dose schedule where efficacy is known to be enhanced in this disease setting, the efficacy was lower than against severe disease. Vaccine effectiveness against any symptomatic disease was 50% against the Beta/Gamma variants, and 70% and 72% against the Delta and Alpha variants, respectively.