London, Feb 4 | Britain on Thursday launched a new clinical study to determine the effects of using different Covid-19 vaccines for the first and second dose, AstraZeneca’s vaccine for one dose and Pfizer-BioNTech’s vaccine for the other.
The study will also gather immunological evidence on different intervals between the first and second dose for a mixed-vaccine regimen against control groups when the same vaccine is used for both doses, the UK’s Department of Health and Social Care said in a statement.
The 13-month study in which over 800 patients are expected to take part will monitor the impact of the different dosing regimens on patients’ immune responses, which have the potential to be higher or lower than from the same dose regimen.
Initial findings are expected to be released in the summer and the results could help understand the vaccines could be safely roll out in a more flexible manner depending on their availability.
Britain said that should the study show promising results it may consider reviewing the vaccine current regimen approach if needed, but only if proven to be safe.
“This is a hugely important clinical trial that will provide us with more vital evidence on the safety of these vaccines when used in different ways,” Nadhim Zahawi, the Minister for Covid-19 Vaccine Deployment in the UK, said in a statement.
“Nothing will be approved for use more widely than the study, or as part of our vaccine deployment programme, until researchers and the regulator are absolutely confident the approach is safe and effective.”
A same-dose regimen is currently implemented for the national Covid-19 vaccination programme, and there are no current plans for this to change, the government said.
Anyone who has received either the Pfizer or AstraZeneca vaccination as part of the UK-wide delivery plan will not be affected by this study.
They will receive their second dose from the same source and over the same 12-week interval.