Japan＊s health ministry on Tuesday approved the first domestically developed COVID-19 vaccine that works against the currently circulating XBB.1.5 sublineage of the omicron variant.

The XBB-adapted version of Daiichi-Sankyo＊s coronavirus vaccine, Daichirona, will be available as a booster under the nation＊s free COVID-19 vaccination program beginning next week.

The government has already decided to procure a total of 1.4 million doses of the vaccine from the drugmaker, the first Japanese firm to have developed COVID-19 shots.

In August, the ministry approved the manufacturing and distribution of Daichirona. But at the time, the shot 〞 a messenger RNA vaccine like those marketed by Pfizer and Moderna 〞 was only based on the original strain of the coronavirus and so it was never used in practice. The drugmaker filed for approval of the XBB version of the same vaccine in September.

COVID-19 vaccines will be offered for free in Japan until March next year to prepare residents for an expected uptick in infections during winter. The health ministry is actively recommending the shot only for people age 65 and older and for those with underlying health conditions.

According to the Tokyo Metropolitan Government, as of Nov. 22, XBB sublineages of the coronavirus accounted for over 90% of all genome-sequenced virus samples in the capital. The most prevalent strain was EG.5, another omicron descendant and a mutated version of XBB.1.9.2, which made up nearly 70% of all sequenced cases.

The health ministry says XBB.1.5 vaccines that are currently used in the vaccination program are effective against EG.5, as their differences are subtle.

Last week, the vaccine subcommittee of the health ministry decided to end the free inoculation program for COVID-19 in March next year, and to make coronavirus shots a routine 〞 like getting an annual influenza vaccine 〞 to be administered for a fee in the fall-winter season. The shots will be modified with the latest variants in mind.

A health ministry panel also approved what have been dubbed ※next-generation§ COVID-19 vaccines using ※replicons,§ or copied RNA, developed by U.S. biotech firm Arcturus Therapeutics. Meiji Seika Pharma applied for the firm＊s replicon COVID-19 vaccine for distribution in Japan earlier this year.

The replicon vaccines feature mRNA that self-replicates inside the body. Self-amplifying RNA vaccines require lower doses than conventional mRNA vaccines because they can reproduce themselves inside immune cells, according to Arcturus Therapeutics.

Meiji Seika has applied for approval of this new type of COVID-19 vaccine using the original strain of the coronavirus. It is currently running a clinical trial for a bivalent shot that also works against the omicron variant. The firm plans to reapply for approval of the replicon vaccine based on the results of the trial.