Question to the Department of Health and Social Care:

To ask Her Majesty's Government, further to the answer by Lord Bethell on 12 January (HL Deb, col 596), what data they have used to determine that delaying a second dose of the Pfizer/BioNTech COVID-19 vaccine beyond 42 days from the first dose is effective and free of risk; and where, if anywhere, this data has been published.

The Joint Committee on Vaccination and Immunisation (JCVI) considered data on the efficacy of a single dose of the Pfizer vaccine. It concluded that a single dose of the Pfizer vaccine would remain highly effective in the weeks following administration. The JCVI’s statement Optimising the COVID-19 vaccination programme for maximum short-term impact: Short statement from the Joint Committee on Vaccination and Immunisation (JCVI) is attached.

Public Health England publishes a monthly report on vaccine effectiveness. The most recent study, published on 17 March, shows that vaccines provide high protection against COVID-19 infections after a single dose, beyond 56 days of having been vaccinated. A copy of Public Health England vaccine effectiveness report is attached.