Dangerous trend: WHO warns against mixing and matching Covid vaccines


By Reuters Staff, published by India Today, and Thai Newsroom

THE World Health Organisation’s chief scientist yesterday (July 12) advised against people mixing and matching Covid-19 vaccines from different manufacturers, calling it a “dangerous trend” since there was little data available about the health impact.

“So it’s a little bit of a dangerous trend here. We’re in a data-free, evidence-free zone here as far as mix-and-match. There is limited data on mix and match. 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,” Soumya Swaminathan said during an online briefing.

Infectious disease experts are weighing whether people who received Johnson & Johnson’s single-dose vaccine should receive a booster of the Pfizer or Moderna mRNA-based vaccine which are said to be more effective against the highly contagious Delta variant.

One of those who did mix and match, Dr. Angela Rasmussen, a researcher at the University of Saskatchewan’s Vaccine and Infectious Disease Organisation, made headlines after she said on Twitter that she had gotten a dose of Pfizer’s vaccine in June after receiving J&J’s in April.

She also advised other J&J recipients, especially those living in areas with low vaccination rates, to talk to their doctors about doing the same.

In Thailand the National Communicable Disease Committee yesterday approved giving  either AstraZeneca or Pfizer booster shot to frontline medical workers with the majority having received two Sinovac jabs over three months ago.

The Thai Public Health Ministry also early this morning said there were 8,685 new coronavirus cases over the past 24 hours with 8,539 being among the general public and 146 in prisons and detention centres, said.

Another 56 patients died taking the death toll 2,847. The total number of patients in the current wave that began in April has now increased to 353,712.

Altogether 3,797 patients were cured over the past day taking total recoveries to 255,455.

Separately, Pfizer is pushing US and European regulators to authorise a third booster shot to supplement its two-dose regimen. But health officials, including the WHO’s Swaminathan, have said there is no medical evidence that a third Pfizer shot is necessary.

“It has to be based on the science and the data, not on individual companies.”

Instead of offering booster shots to highly-vaccinated, wealthy nations, the WHO’s director-general yesterday said companies like Pfizer should send those vaccines to the WHO to give to poorer countries whose unvaccinated citizens desperately need them against a Delta variant she described as “ripping around the world at a scorching pace.”


Top: An image illustrating the mixing of two different Covid-19 vaccines. Photo:

Home Page: World Health Organization (WHO) Chief Scientist Soumya Swaminathan attends a press conference organised by the Geneva Association of United Nations Correspondents (ACANU) amid the Covid-19 outbreak, caused by the novel coronavirus, at the WHO headquarters in Geneva, Switzerland on July 3, 2020. Photo: Fabrice Coffrini/Pool via REUTERS and published by Channel NewsAsia


Leave a Reply