Mix and match Covid vaccine study finds rise risk of symptoms

May 14, 2021: -A major U.K. trial assessing the benefits of mixing and matching Covid-19 vaccines has found that volunteers who received alternating doses were more likely to develop mild to moderate symptoms.

On Wednesday, it reported that preliminary data shows participants receiving a mixed schedule of coronavirus vaccines incurred more frequent reactions than the ones on the standard non-mixed programs.

The mild to moderate symptoms reported in the participants who take a mixed vaccine schedule include chills, fatigue, feverishness, headache, joint pain, muscle ache, and pain at the injection site.

The adverse reactions were found to be short-lived, and there were no other safety concerns. The data was recorded in participants who are 50 and above.

There is a possibility that adverse reactions to mixed coronavirus vaccines may be more prevalent in younger aged people, researchers said.

It is thought that a varied dosing schedule could lead to a surge in work absences the day after vaccinating against the coronavirus.

On Wednesday, in a peer-reviewed research letter published in The Lancet international medical journal, researchers of the trial report that when given at a four-week interval, both the Oxford-AstraZeneca vaccine and the Pfizer-BioNTech vaccine induced more reactions frequently following the second dose than the standard non-mixed schedules.

“While this is a secondary part of what we are trying to explore through these studies, it is important that we inform people about these data, especially as these mixed-doses schedules are being considered in several countries,” Matthew Snape, associate professor in Paediatrics and Vaccinology at the University of Oxford, said.

“The results from this study suggest that mixed dose schedules could increase work absences the day after immunization, and this is important to consider when planning immunization of health care workers,” he added.

The aim of the study is to evaluate the feasibility of mixing and matching Covid vaccines to help policymakers understand if this could be a viable route to make the flexibility of vaccination campaigns high.

Initially, the trial recruited 830 volunteers aged 50 years and above. In April, researchers expanded the program, including the Moderna and Novavax Covid-19 vaccines, in a study known as “Com-COV2.” This added a further 1,050 volunteers to the program.