A trial to confirm if Covid vaccine types can be mixed is underway - what we know so far

Volunteers are being recruited to take part in a world first study to examine the effects of mixing and matching Covid-19 vaccines.

The trial will be conducted on more than 800 participants over the age of 50, and will compare the effects of issuing one dose of the Oxford/AstraZeneca vaccine and one dose of the Pfizer/BioNTech vaccine.

The intervals between the doses will be either four or 12 weeks, in order to test the effects of waiting longer between jabs on the immune response.

‘No current plans to change vaccination programme’

In a statement from the Government announcing the study, it explains that a “same-dose regimen is currently implemented for the national Covid-19 vaccination programme, and there are no current plans for this to change”.

This means that anyone who received either the Oxford/AstraZeneca vaccine or the Pfizer/BioNTech vaccine will not be affected by the study, and will receive their second dose from the same vaccine over the same 12 week interval.

The study is being run by the National Immunisation Schedule Evaluation Consortium (NISEC) across eight National Institute for Health Research (NIHR) supported sites.

These eight sites are situated in locations across England, in London (St George’s and UCL), Birmingham, Liverpool, Oxford, Southampton, Bristol and Nottingham.

Patients for the study will be recruited over the course of February, with volunteers recruited via the NHS Covid-19 Vaccine Research Registry. Vaccinations are expected to start towards the middle of the month, with initial results made available over the summer period.

Members of the public can volunteer to take part in the study, and further vaccine studies, by joining the registry.

Official guidance advises against mixing vaccines