The lead scientist at the World Health Organization (WHO) advises against combining Covid-19 vaccines from different pharmaceutical companies, saying that decisions should be left to public health authorities. Soumya Swaminathan’s warning came after Vietnam said citizens vaccinated with one dose of AstraZeneca can choose whether they want the second dose to be from the same drugmaker or from Pfizer.
“It’s a rather dangerous trend,” Soumya Swaminathan said in an online interview this week after asked about the possibility of needing booster shots. “It will be a chaotic situation if citizens start to decide when and who will take the second, third and fourth doses”, continued the scientist.
+ Thailand advocates mixing vaccines despite WHO warning
The WHO scientist noted that vaccine mixtures are still a “data-free zone”. “Individuals should not decide for themselves, public health agencies can, based on available data,” he clarified on Twitter. According to Swaminathan, WHO is still awaiting the results of studies of the mixture of different vaccines, where “immunogenicity and safety need to be evaluated”.
According to the British newspaper “The Guardian”, some studies have already started to show positive results in the vaccine mixture, but that the studies are still at a very early stage.
To date, only a few countries combine vaccines from different manufacturers, namely countries where vaccines do not arrive in sufficient doses. The effects of the AstraZeneca vaccine also led to discomfort in several countries, with Spain, Canada and South Korea opting for a different vaccine for the second dose.
+ Learn about the effectiveness of each vaccine against Covid-19