Mixing different brands of COVID-19 vaccines may result in a better immune response than sticking to one brand, says a British study. According to their findings, flexible dosing may be an effective option for developing and lower-income nations.
An Oxford study has found flexible dosing to be as safe and effective as single-brand vaccination—if not more so. The findings suggest that someone who received a first dose of AstraZeneca/Pfizer-BioNtech, followed by a Moderna shot nine weeks later, produced “robust immune responses” against COVID-19.
The study, called Com-COV, was led by Matthew Snape, an associate professor in pediatrics and vaccinology at Oxford University. 1,070 participants were included and observed.
The non-inferiority study sought to investigate if mixing different vaccine brands was inherently less effective than using two doses of the same type. Immune responses among participants were compared to the findings established in the clinical trials of approved vaccines. The researchers found that having an AstraZeneca first dose coupled with a Moderna/Novavax second dose resulted in higher antibodies and T-cell responses than using AstraZeneca for both doses. When replicated with Pfizer, the findings were the same.
“We found a really good immune response across the board,” Snape said.
“In fact, higher than the threshold set by Oxford-AstraZeneca vaccine two doses.”
No safety concerns were identified by the study.
“Thanks to studies such as these, we are now getting a more complete picture of how different COVID-19 vaccines can be used together in the same vaccine schedule,” said Snape.
“We’re showing…you don’t have to stick rigidly to receiving the same vaccine for a second dose…and that if the programme will be delivered more quickly by using multiple vaccines, then it is okay to do so.”
The findings could be highly valuable to developing and lower-income nations, which will now have evidence to support the use of mixed or flexible dosing. For countries lagging behind with their vaccine rollouts, this data suggests they may benefit from an expedited process through flexible dosing as opposed to waiting for more stock of a single brand.