Question to the Department of Health and Social Care:

To ask Her Majesty's Government what is the optimum gap between the first and second dose of (1) the Oxford/AstraZeneca, and (2) the Pfizer/BioNTech, COVID-19 vaccine for securing the longest period of protection against COVID-19.

The Medicines and Healthcare products Regulatory Agency’s (MHRA’s) Information for Healthcare Professionals regarding the Pfizer vaccine states that a second dose of it should be given at least 21 days after the first dose. For the AstraZeneca vaccine, the Information for Healthcare Professionals states that the second dose should be given between four and 12 weeks after the first dose. This advice is based on clinical trial data and other information submitted to MHRA by the manufacturer.

Based on trial data showing the effectiveness of both vaccines, the Joint Committee on Vaccination and Immunisation (JCVI) advised that both vaccines should be given up to 12 weeks apart. The JCVI also advised that priority should be given to having a greater number of people given a first dose, which would have a greater public health impact than prioritising second doses.