A closed shop in Thai capital Bangkok displays the sentence 'We'll survive' on the first day of Covid-19 lockdown restrictions to try to contain the spread of the virus on July 12. (Photo: AFP)
The World Health Organization (WHO) has warned governments and health authorities around the world against mixing and matching Covid-19 vaccinations.
WHO chief scientist Soumya Swaminathan said in an online briefing that there was little data available about the health impact of mixing vaccines from different manufacturers but a dangerous trend was emerging.
“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. 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.
“I really want to caution folks because there is a tendency now for people in countries with enough availability of vaccines to voluntarily start thinking.”
Some countries, including Germany and Canada, are encouraging people who get a first dose of the AstraZeneca vaccine to get an mRNA vaccine, such as Pfizer or Moderna, for their second dose.
The WHO warning also followed reports in Asia that vaccines that normally require two jabs were being mixed, raising concerns of shortages and distribution issues.
One report has found that mixing vaccines was more likely to cause side effects
Many countries, particularly in the developing world, are relying on Russia, China, India and Western counties to provide an assortment of vaccines through outright purchases or donations. They are acquired on their abilities to store and refrigerate.
One report has found that mixing vaccines was more likely to cause side effects.
In Thailand, the Bangkok Post reported a major policy change after the Public Health Ministry decided to use the AstraZeneca vaccine as the second jab for those who received Sinovac as their first dose.
Health Minister Anutin Chanvirakul announced the change on July 12, saying AstraZeneca would be administered as the second shot three or four weeks after the first Sinovac inoculation.
Despite the lack of science, he said a combination of the two vaccines would provide a better defense against the Delta variant, the dominant strain which has taken hold across the country.
The report noted that Anutin did not say what people who have had two doses of Sinovac should do when the change in policy comes into force, or how it would affect people awaiting their first or second dose of the AstraZeneca vaccine.
However, the Thai government also plans to use 1.5 million donated doses of the Pfizer vaccine to provide healthcare workers with a third, or booster, dose.
India is also mulling mixing Covishield and Covaxin, but it has not been implemented. However, health authorities have acknowledged that there have been some accidental mix-ups of the different vaccines.
Swaminathan said some studies into mixing vaccines had shown promise but she added that despite the spread of the different types of coronavirus variants, booster shots were still not needed, although this could change.