COVID vaccine mix increases risk of side effects – study

Mixing different coronavirus vaccines can increase your risk of experiencing mild to moderate side effects, according to a study conducted by the University of Oxford.

The issue of mixing different vaccines has been raised due to efforts to avoid supply shortages and changing recommendations for some vaccines with reported serious side effects.

Recently published data was collected from self-reported symptoms collected seven days after the first and second vaccine doses from participants who received the vaccines at 28-day intervals.

Both groups reported experiencing mild to moderate side effects at a higher rate than those who received the same vaccine both times. For example, fever was reported to be nearly double the rate by those who received the Pfizer vaccine and then the AstraZeneca vaccine (41%) compared to those who received the Pfizer vaccine only for both doses (21%).

Participants reported similar increases for chills, fatigue, headaches, joint pain, discomfort and muscle pain, according to the study.

None of the participants were hospitalized for their side effects, and most side effects were experienced within 48 hours of receiving the vaccine.

Paracetamol use also increased in those who received different vaccines for each dose compared to those who received the same vaccine for both doses.

The researchers noted that the participants were all aged 50 or older and that younger groups may have higher rates of mild to moderate side effects after receiving two different vaccines.

Other studies integrating the Moderna and Novavax vaccines are currently underway.

“While this is a side part of what we’re trying to explore through these studies, it’s important that we let people know about this data, especially since these mixed-dose regimens are being considered. in several countries, ”said Matthew Snape, associate professor of Pediatrics and Vaccinology at the University of Oxford, and chief investigator of the trial, in a press release from the University of Oxford. “The results of this study suggest that mixed dosing regimens could lead to an increase in absence from work the day after vaccination, and it is important to take this into account when planning the vaccination of health workers.

“Importantly, there are no safety issues or signals, and that doesn’t tell us if the immune response will be affected,” Snape added.

The main goal of the study is to understand how the vaccine mix affects the immune response, with the researchers saying the results regarding the immune response are expected to be released in June.