Over 35 million people across the UK have now had their first dose of the Covid vaccine. Over 18 million have also received their second dose and are considered "fully vaccinated."
Earlier this year, there was speculation over whether vaccines could be combined. However, the results of a recent study led by the University of Oxford show that combining the Oxford and Pfizer vaccines could mean a greater risk of side effects such as shivers, headaches, and muscle pains.
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Short-term adverse reactions
The good news is that the study also suggests that the side effects are short-term ones, and aside from the increased risk of these effects, no other safety issues came to light.
Following the preliminary release of the Com-Cov study results, Prof Matthew Snape, from the Oxford Vaccine Group, said, "It's a really intriguing finding and not something we were necessarily expecting."
There were various reasons why mixing vaccines was being considered and studied. One of the key ones was determining whether people could gain longer-lasting immunity receiving different vaccines for the first and second doses. In addition, some hoped that it would result in better protection against the string of new variants that continue emerging.
Another reason health officials wanted to learn about mixing vaccines was to overcome any issues with supplies more easily. The ability to combine different vaccines for the two doses would allow clinics to continue without interruption if there was an issue with one particular vaccine supply.
Some countries already planning to use a combination of vaccines
Despite the increased risk of side effects, there appear to be no other safety issues, which means many regions may decide to mix their vaccines. Health officials have already confirmed this in Quebec and Ontario, where they will be using a combination of vaccines soon.
The study saw over 800 volunteers aged 50 and over taking part, with the full outcome of the study is set to be released in June.