With the coronavirus outbreak continuing to leave a trail of devastation across the country, several pharmaceutical companies and vaccine manufacturers across the world are racing against time to produce jabs that aid efforts to shield people from the deadly virus.

While there are several single-dose and double-dose vaccines currently doing the rounds, some pharma majors are also working on a ‘cocktail’ of vaccines in order to increase its potency.

However, World Health Organisation (WHO) chief scientist Soumya Swaminathan on Monday said that mixing and matching the Covid-19 vaccines is a “dangerous trend” which could lead to a disaster as there is very little data on its efficacy.

“Really want to caution folks, because there is a tendency now for people in countries which enough availability of vaccines to voluntarily start thinking. So it’s a little bit of a dangerous trend here where we are in a data-free evidence-free zone as far as a mix and match there is limited data on mix and match. There are studies going on, we need to wait for that,” Swaminathan said while addressing a media briefing on Covid-19.

The top WHO scientist said that booster shots will lead to a “chaotic situation” if citizens start deciding when they should take a second, third, or fourth dose.

“We have four countries that have announced a booster program, and a few more that are thinking about it. If 11 high and upper-middle-income countries decide to some of them are large countries that they will go for a booster for their populations or even subgroups. This will require an additional 800 million doses of vaccine,” she said.

Swaminathan, however, stressed on the need to prioritise vaccines as there are countries even now where frontline and health care workers have not been vaccinated, along with the elderly and the vulnerable