The UK's COVID-19 Vaccination Policies Find Clinical Support

The Lancet published a commentary on March 6, 2021, which highlighted the positive impact of the single-dose Oxford–AstraZeneca COVID-19 vaccine followed by a 12-week booster.

Overall, this study provides evidence that a single dose of the ChAdOx1 nCoV-19 vaccine is highly efficacious in the 90 days after vaccination. And that a longer prime-boost interval results in higher vaccine efficacy. Furthermore, the protection against symptomatic COVID-19 is maintained despite a longer dosing interval.

In exploratory analyses, vaccine efficacy after a single standard dose was 76% from day 22 to day 90, and antibody levels were maintained during this period with minimal waning. Supporting a longer-interval immunization strategy, vaccine efficacy was significantly higher at 81% after two standard doses are given at an interval of 12 weeks or longer, compared with 55% when given less than 6 weeks apart.

This analysis offers supporting evidence for the United Kingdom's policies of extending the AstraZeneca COVID-19 vaccine dosing interval to 12 weeks and for rapid mass-immunization campaigns worldwide.