Photo/Illutration The vaccine developed by Novavax Inc. (Provided by Novavax Inc.)

The health ministry officially approved the new coronavirus vaccine developed by Novavax Inc. on April 19, a day after its expert panel gave it the green light for use in Japan.

That makes the U.S. biotech giant’s vaccine the fourth available in Japan, following the mRNA vaccines made by Pfizer and Moderna, and AstraZeneca’s viral vector vaccine.

Novavax’s shot is a kind of “recombinant protein vaccine,” which is different from the other kinds. It includes a reconstructed protein found on the surface of the coronavirus, as well as an extra ingredient that stimulates an immune response, to help the body identify the virus and learn to attack it.

It is expected to be made available for people who develop allergic reactions to the other types of vaccines.

It can also be manufactured domestically.

“We will secure a stable supply of vaccines in case of possible export controls by other countries,” said health minister Shigeyuki Goto.

According to the health ministry, the Novavax vaccines will be shipped across Japan as early as May 23.

They will be used for people who are receiving their COVID-19 vaccination shots for the first, second or third time.

People 18 or older are eligible for the vaccine. Unvaccinated people will be given the second shot at least three weeks after the first one.

Clinical tests for the first two shots, which were conducted in the United States and elsewhere, showed that the vaccine decreased the risk of developing symptoms by 90.4 percent.

The results were obtained prior to the spread of the Omicron variant, but the ministry judged during its screening process that the vaccine should be sufficiently effective.

Of the patients who received their second shot, 44.5 percent reported having a headache and 48.1 percent experienced muscle pain, while 5.7 percent developed a fever of 38 degrees or higher.

“The clinical tests proved the Novavax vaccine was highly effective, matching that of mRNA vaccines,” said Tetsuo Nakayama, a specially appointed professor at the Omura Satoshi Memorial Institute of Kitasato University. “People who couldn’t use the previous vaccines can have another alternative.”

He added that since the vaccine is manufactured in a conventional method, people “might feel it is somewhat safer than others.”

The major drug manufacturer Shionogi & Co. has been developing the same type of coronavirus vaccine, and other domestic companies are also continuing their work developing multiple types of vaccines against the novel coronavirus.

Nakayama said “late-comer” vaccines have a significant role to play.

“Vaccines are our weapons to fight infectious diseases,” he said. “Even if they are developed later than others, more choices of vaccines and Japan’s capability to manufacture them will lead to being better prepared for the next pandemic.”

Last September, the government signed a contract to receive a supply of about 150 million doses of the Novavax vaccine from Takeda Pharmaceutical Co., which is responsible for manufacturing and distributing the vaccine in Japan.

At the same time, the health ministry said that Sotrovimab, a neutralizing antibody drug that has already been available for medical treatment, could be less effective against the BA.2 Omicron subvariant.

The ministry has changed the package inserts, or the drug usage instructions, for the remedy, so that it said the drug “should be considered for use in cases where any others are unavailable.”

(This article was written by Kai Ichino and Kenta Noguchi.)