Japan may consider mixing shots for speedier vaccinations

TOKYO • Japan could mix AstraZeneca's Covid-19 shots with those developed by other companies to speed up its vaccination efforts, according to the minister in charge of the country's roll-out.

The idea would be to combine the dose with one from Pfizer and BioNTech or Moderna, Mr Taro Kono said yesterday on a Fuji TV news programme.

Since AstraZeneca recommends eight weeks between its two shots, it is likely that time could be shortened if combined, Mr Kono added.

Studies on mixing Covid-19 vaccines so far show that it could result in an equal if not stronger immune response. But it is not clear which combination could give the best protection that will last the longest, with some evidence that mixing could cause worse side effects.

Countries like Canada, Germany and France allow mix-and-match vaccines, but the United States 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," Mr Kono said.

If mixing is allowed, he said it would also increase the options for a potential third shot that Japan is considering.

About 44 per cent of the population are fully vaccinated, including nearly 90 per cent of those over the age of 65. Still, a majority of younger people have not been inoculated. 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 government did not make it immediately available, taking a cautious stance on reports of related blood clots.

Most of the shots are being produced domestically and do not rely on imports. Japan has almost two million AstraZeneca doses on hand, Mr Kono said.

Separately, Japan is investigating the deaths of two people who were administered Moderna's shots from vaccine batches that have since been suspended.

While the relationship between the deaths and the shots is currently unclear, the health ministry will conduct the investigations together with external experts, and continue to assess the safety of the vaccine, according to a statement last Saturday.

Doses from three lots have been halted following reports that foreign particles were found in one of the batches. The two people received their second shots from a lot that did not have any foreign particles reported, but it was suspended because the batch was produced at the same facility around a similar time.

The two deaths, both men in their 30s, were confirmed three days after they received their second Moderna shots this month, the health ministry said. Neither of them had a history of allergies or other underlying conditions.

Moderna and Takeda Pharmaceutical, the local distributor of the shot, said it was important the relationship between the deaths and the shots is investigated.

Japan's Health Minister Norihisa Tamura said on national broadcaster NHK yesterday that the investigation into the cause of the deaths is ongoing.

BLOOMBERG