According to reports the vaccines are likely to be safe and effective but the researchers are still gathering data to be sure. The coronavirus shots which are authorized around the world are all designed to stimulate our immune system to produce virus-fighting antibodies, though they do vary, stated, Dr. Kate O’Brien, director of the World Health Organization’s vaccine unit.
“Based on the basic principles of how vaccines work, we do think that the mix-and-match regimens are going to work,” she said.
“We really just need to get the evidence in each of these (vaccine) combinations,” O’Brien said.
However, limited data is present there that suggests an AstraZeneca shot followed by the Pfizer shot is safe and effective so far. Scientists at Oxford University in the United Kingdom are testing combinations of the two-dose COVID-19 vaccines made by AstraZeneca, Moderna, Novavax, and Pfizer-BioNTech. Smaller trials are also ongoing in Spain and Germany.
While the combination of the shots appears to show some temporary side effects like aches and chills that might be because of mixing and matching different types of vaccines can often produce a stronger immune response noted, Lawrence Young, a virologist at the University of Warwick in the United Kingdom.
After the AstraZeneca vaccine reported to be linked to extremely rare blood clots, many European countries including Germany, France, and Spain recommended people who got it as a first dose get a Pfizer or Moderna shot as a second dose instead.
Moreover, health officials, in some places already suggest mixing in select circumstances.
Officials say, people in Britain and Canada should aim to get the same vaccine for their second dose if possible.
In case they got AstraZeneca as their first dose then they are advised to get another vaccine shot only if they have a history of blood clots or other conditions that might put them at higher risk of clots.