Question to the Department of Health and Social Care:

To ask Her Majesty's Government what estimate they have made of the duration of protection from COVID-19 provided by (1) the Oxford/AstraZeneca, and (2) the Pfizer/BioNTech, vaccine; and what estimate they have made of the length of time a person who receives (a) only a first dose, and (b) two doses, of (i) the Oxford/AstraZeneca and (ii) the Pfizer/BoNTech, vaccine is protected from COVID-19.

The total length of protection from vaccines against COVID-19 is not yet fully understood. Vaccine developers and manufacturers continue to collect data on the performance of their vaccines. Through their surveillance strategy Public Health England (PHE) continues to assess the effectiveness of vaccines, including duration of protection. A copy of PHE’s COVID-19 vaccine surveillance Strategy is attached.

On 26 January the Joint Committee on Vaccine and Immunisation (JCVI) published an online report, Optimising the COVID-19 vaccination programme for maximum short-term impact. The report found that short-term vaccine efficacy from the first dose of the Pfizer/BioNTech vaccine is calculated at around 90% and from the first dose of the Oxford/ AstraZeneca vaccine is calculated at around 70%, with high protection against severe disease.

Given the high level of protection afforded by the first dose, models suggest that initially vaccinating a greater number of people with a single dose will prevent more deaths and hospitalisations than vaccinating a smaller number of people with two doses. The second dose is important to provide longer lasting protection and is expected to be as or more effective when delivered at an interval of 12 weeks from the first dose. The JCVI has based their advice on the assumption that protection from a first dose of either vaccination will wane in the medium term and that a second dose will offer more long term protection.