Countries weigh 'mix and match' Covid-19 vaccines

Europe's drug regulator had made no definitive recommendations on switching vaccines. PHOTO: AFP

LONDON (REUTERS) - A growing number of countries are looking at switching to different Covid-19 vaccines for second doses or booster shots after supply delays and safety concerns slowed their vaccination campaigns.

The World Health Organisation (WHO) said on July 12 that the practice was a dangerous trend since there was little data about the health impact. Europe's drug regulator on July 14 made no definitive recommendations on switching vaccines.

The following countries are considering, or have decided to adopt, such an approach:


A British study is looking into the immune responses of children to mixed schedules of different vaccines.

Officials said that while the recipients will be given a first dose of the Pfizer-BioNTech shot, advice about second doses will be provided at a later date, while more data is gathered.

Britain is preparing for a "mix and match" Covid-19 vaccine booster programme, the Financial Times reported on Sept 10.


Cambodian Prime Minister Hun Sen said on Aug 1 that a booster shot of AstraZeneca's vaccine would be offered to people who had received two doses of shots from either Sinopharm or Sinovac, while a Sinovac booster should be given to Cambodians fully inoculated with the AstraZeneca shot.


Denmark's State Serum Institute, which deals with infectious diseases, said on Aug 2 that combining AstraZeneca's vaccine with a second shot from either Pfizer-BioNTech or Moderna provides "good protection".


Germany will offer booster shots of the Pfizer-BioNTech and Moderna vaccines from September to vulnerable individuals such as pensioners and people with weak immune systems, regardless of which vaccine they had previously received.


Russia's Direct Investment Fund (RDIF) said on Sept 27 that a small-scale clinical study combining the AstraZeneca and Sputnik Light shots had shown strong antibody growth in a majority of the study's participants.


Turkey is allowing people who have been inoculated with Sinovac's vaccine to receive an additional Pfizer dose as it looks to ease travel to countries that have not approved the Chinese shot, Turkey's health ministry said on Aug 16.

United States

US regulators authorised a third dose from either Pfizer-BioNTech or Moderna on Aug 13 for people with compromised immune systems who are likely to have weaker protection from two-dose regimens.

If a recipient's original shot is not available, they can be vaccinated with the other one.

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