Question to the Department of Health and Social Care:

To ask the Secretary of State for Health and Social Care, with reference to the findings of the Com-COV study on the immune response from mixing covid19 vaccines, whether his Department has made an assessment of the potential merits of providing a different type of covid-19 vaccine from a recipient's original dose as a booster.

The Com-CoV vaccine trial is studying the use of different combinations of approved COVID-19 vaccines for the first and second immunisation doses. The COV-BOOST trial is studying combinations of different COVID-19 vaccines for a booster dose following completion of the primary two-dose course. Data from the trial indicates that booster doses of COVID-19 vaccines are generally well tolerated and provide a substantial increase in vaccine-induced immune responses.

The Joint Committee on Vaccination and Immunisation has advised that a full dose of Pfizer-BioNTech vaccine or a half dose of the Moderna vaccine should be offered as a booster dose, irrespective of the vaccine used for the first two doses.