Mixing and matching Covid-19 vaccines ‘dangerous trend’: WHO’s chief scientist Soumya Swaminathan

The World Health Organization’s (WHO’s) chief scientist Dr Soumya Swaminathan has warned against mixing and matching of Covid-19 vaccines by different manufacturers for the first and second doses, calling it a “dangerous trend” and saying that there was a lack of data about the impact of the process.

“There are people who are thinking about mixing and matching. We receive a lot of queries from people who say they have taken one [dose] and are planning to take another one (doses). It’s a little bit of a dangerous trend here. We are in a data-free, evidence-free zone as far as mix and match,” Swaminathan said in an online briefing earlier in the day.

“There is limited data on mix and match. There are studies going on, we need to wait for that. Maybe it will be a very good approach. But, at the moment we only have data on the Oxford-AstraZeneca vaccine, followed by Pfizer. It will be a chaotic situation in countries if citizens start deciding when and who will be taking a second, a third and a fourth dose,” she said.