Photo/Illutration The vaccine developed by Moderna Inc. arrives at Kansai International Airport on May 13. (Takuya Nishie)

Two additional vaccines for the novel coronavirus were approved by the health ministry on May 21, but only one will be widely used in the near future.

The vaccines are manufactured by Moderna Inc. and AstraZeneca Plc.

The government has signed contracts with Moderna for enough doses for 50 million people, and the vaccine is expected to be used at mass inoculation programs in Tokyo and Osaka from May 24.

The contract with AstraZeneca is for enough doses for 60 million people, but due to reports from abroad of the vaccine causing side effects in rare cases that lead to thrombosis, further studies will be conducted before deciding who it can be administered to.

The two vaccines were given the green light under a special approval procedure based on the results of clinical testing overseas, such as the vaccine jointly developed by U.S. pharmaceutical company Pfizer Inc. and German biocommerce company BioNTech, which is now being used on senior citizens.

Moderna’s vaccine must be stored at minus 20 degrees, and like Pfizer’s vaccine, uses genetic material called Messenger RNA.

AstraZeneca’s vaccine can be stored under refrigeration at around 2 to 8 degrees and uses a virus vector that delivers necessary genetic material.

Two shots will be required for effective immunization.