Can you mix and match two shots of Covid-19 vaccines? Is it safe to take two different shots of vaccines? Like taking the first dose of Covaxin and the second shot of Covishield or Sputnik V or vice-versa? While researchers are still gathering data to be sure about the results of mixing and matching Covid vaccine doses, the World Health Organization has warned against it.
WHO chief scientist Dr Soumya Swaminathan has called it a dangerous trend during an online briefing on the issue.
“Individuals should not decide for themselves, public health agencies can be based on available data,” she said in a tweet after the briefing. “Data from mix and match studies of different vaccines are awaited – immunogenicity and safety both need to be evaluated,” she further added.
What studies say on mixing of Covid vaccines
Some studies are showing positive results from mixing vaccines, but further studies to support them are still awaited. Mix and match of vaccines are seen as an option in some countries where supply is short of one particular vaccine. A study led by Oxford University has discovered that alternating doses of the AstraZeneca and Pfizer-BioNTech vaccines generate robust immune responses against the coronavirus disease. The study, published on the Lancet pre-print server, says “mixed” doses of these vaccines induced high concentrations of antibodies against the SARS-CoV2 spike IgG protein when they were given four weeks apart.
What WHO advisory group said on mixing of vaccines
The WHO Strategic Advisory Group of Experts on vaccines said in June the Pfizer Inc vaccine could be used as a second dose after an initial dose of AstraZeneca if the latter is not available.
Mixing and matching of Covid-19 vaccines is a method of vaccination using two doses of the shot from different manufacturers. Most vaccines including those of Pfizer-BioNTech, Moderna, AstraZeneca, Bharat Biotech as well as Sputnik V, are all required to be administered in two doses with the prescribed intervals between the shots differing for each vaccine. Sputnik V also has a single-dose vaccine named Sputnik V Lite and the jab by Johnson & Johnson is a single-dose vaccine too.