Question to the Department of Health and Social Care:

To ask the Secretary of State for Health and Social Care, what assessment his Department has made of the effectiveness of the AstraZeneca vaccination against (a) catching (b) cases of severe illness deriving from, and (c) hospitalisations arising from the Omicron covid-19 variant.

The UK Health Security Agency (UKHSA) publishes weekly COVID-19 vaccine surveillance reports, including the latest evidence on vaccine effectiveness against different outcomes, comparing rates of disease in vaccinated individuals to rates in unvaccinated individuals. The most recent assessment published on 17 February 2022 states that after two doses of the AstraZeneca vaccine, effectiveness against infection of the Omicron variant, starts at approximately 50% then reduces to almost no effect from 20 weeks after the second dose. After a booster dose with an mRNA vaccine, this increases to 60 to 70% then wanes to approximately 30% by 15 weeks and over after vaccination.

The UKHSA uses hospitalisation as an indicator of severe diseases. Two doses of either AstraZeneca vaccine was associated with a vaccine effectiveness of approximately 35% against hospitalisation following infection with the Omicron variant, after 25 weeks and over. After a booster dose with an mRNA vaccine, this increases to approximately 80 to 90%.