(Bloomberg) -- Pfizer Inc. and Moderna Inc.’s Covid-19 vaccines targeting the omicron variant were approved by Japan’s health ministry late Monday, paving the way for them to be rolled out in the world’s third-largest health-care market. 

The ministry endorsed the shots shortly after an expert panel advised deploying the boosters. Pfizer’s omicron booster can be administered to Japanese aged 12 and over, the panel advised, while Moderna’s should be limited to those 18 and above.

Japan is the latest country to sign off on the targeted boosters following similar approvals by the US, UK and Australia in the past couple of months. South Korea and Taiwan have only authorized Moderna’s shot. Public health authorities are looking to the updated inoculations to sharpen their Covid response as the coronavirus continues to mutate, allowing for breakthrough infections. 

Both Pfizer and Moderna’s vaccines target two strains -- the original version of the virus as well as BA.1, an early version of the omicron variant that spread across the world last northern hemisphere winter. The first set of Covid vaccines rolled out in late 2020 and still being administered throughout the world were developed for the original novel coronavirus strain first detected in the central Chinese city of Wuhan. 

Besides Pfizer and Moderna, Sanofi, GSK Plc as well as China’s Sinovac Biotech Ltd. and Sinopharm Group Co. are developing new shots targeting omicron, which produces milder Covid infections in most cases but has emerged as the most prevalent variant globally. 

What We Know About the Omicron Group of Virus Variants: QuickTake

Recent research has found that the variant-modified shots are slightly more effective than the original vaccines. Antibodies that neutralize the virus jump about 11-fold after a booster targeting the original strain, but they increase a further 1.5-fold with a targeted booster, researchers at the University of New South Wales’ Kirby Institute found last month. 

Japan is planning to expedite a rollout of the boosters originally planned for October so as to better prepare for winter, Prime Minister Fumio Kishida has said. The booster will be available free of charge for those eligible if they have already received at least two Covid shots previously.

(Updates from first paragraph to reflect ministry’s approval of shots)

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