An updated COVID-19 vaccine targeting the Omicron XBB.1.5 subvariant became available in Japan on Wednesday ahead of an expected surge in infections around the year-end holidays.

The free vaccination campaign, in which anyone six months or older is eligible, will continue through the end of March, with the elderly and other high-risk populations encouraged to get protection.

The XBB.1.5 subvariant is known for mutations that appear to help it evade the body's immune defenses and improve its ability to invade cells. The updated vaccine is also believed to be effective against the Omicron subvariant EG.5.1 that has spread in Japan.

A man receives an updated COVID-19 vaccine at a clinic in Tokyo's Minato Ward on Sept. 20, 2023. (For editorial use only)(No reuse permitted)(Kyodo)

Recipients of the booster shot, mostly manufactured by U.S. companies Pfizer Inc. and Moderna Inc., should have waited at least three months from their most recent inoculation against the novel coronavirus. They can also get flu shots at the same time.

Some areas may see a delay in the start of inoculations depending on the delivery situation of the vaccine.

The vaccination this fall might be the last chance to obtain coronavirus inoculation in Japan free of charge, as the government is set to end next March its special measures that have allowed the public to get shots without payment.

The government in May downgraded the legal status of COVID-19 to the same category as common infectious diseases like seasonal flu.

The Ministry of Health, Labor and Welfare is considering converting the status of COVID-19 vaccinations to a regular inoculation program, offering shots for people aged 65 and above and other high-risk populations to get one shot between fall and winter.

Free coronavirus vaccines have been available from February 2021 in Japan, starting with health care professionals before being expanded to the general public.

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