Japan May Consider Mixing Covid Shots for Speedier Vaccinations


Japan could mix AstraZeneca Plc’s Covid-19 shots with those developed by other companies in order to speed up its vaccination effort, according to the minister in charge of the country’s rollout.

The idea would be to combine the dose with one from Pfizer Inc. and BioNTech SE or Moderna Inc., Taro Kono said Sunday on a Fuji TV news program. Since AstraZeneca recommends eight weeks between its two shots, it’s likely that time could be shortened if combined, Kono added. 

Studies on mixing Covid vaccines so far show that it could result in an equal if not stronger immune response. But it’s not clear which combination could give the best protection that will last the longest, and there’s some evidence that mixing could cause worse side effects. Countries like Canada, Germany and France allow mix-and-match vaccines, but the U.S. has warned against doing so.  

“I’m asking the health ministry to issue its point of view on whether it’s OK to mix the vaccines,” Kono said. If mixing is allowed, he said it would also increase the options for a potential third shot that Japan is considering.

Vaccinations in Japan, which started late compared to other developed nations, has progressed quickly since early summer. About 44% of the population is fully vaccinated, including nearly 90% of those over the age of 65. Still, a majority of younger people haven’t been inoculated and they have been the worst affected during its current surge of infections.

All three vaccines are approved for use in Japan, but most of the 124.5 million doses given have used Pfizer and Moderna. AstraZeneca was approved in May, although the Japanese government did not make it immediately available, taking a cautious stance on reports of related blood clots.

Last month, Japan began to allow a limited rollout of AstraZeneca vaccine to those over the age of 40 that wanted to take it. Most of the shots are being produced domestically and don’t rely on imports. Japan has almost two million AstraZeneca doses on hand, Kono said. 

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