Safety and efficacy of an rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine: an interim analysis of a randomised controlled phase 3 trial in Russia
RCT of the Sputnik V COVID-19 vaccine (n=21,977) found that after 21 days from first dose, those given the vaccine had a significantly lower rate of confirmed COVID-19 (0.1% vs 1.3%; efficacy 91.6%, 95%CI 85.6-95.2). Serious adverse events were similar between groups.
Source:
The Lancet
SPS commentary:
A commentary piece reviews this study. It points out that a time-resolved plot of the incidence rate in the two groups showed that the immunity required to prevent disease arose within 18 days of the first dose. That protection applied to all age groups, including those older than 60 years, and the anecdotal case histories of those vaccinated but infected suggest that the severity of disease decreases as immunity develops. The commentary concludes that the positive results, and also the suggested lessening of disease severity after one dose is particularly encouraging for current dose-sparing strategies.