Photo/Illutration Elderly residents in Fukuoka Prefecture receive third doses of the COVID-19 vaccine on Jan. 5 at a mass vaccination center in the prefecture’s Chuo Ward. (Shoma Fujiwaki)

KOBE--Japanese getting booster shots of a COVID-19 vaccine significantly increased their neutralizing antibody levels against the Omicron variant of the novel coronavirus, according to a new study.

A team of researchers from Kobe University and the Hyogo prefectural government announced the results on Jan. 18 of a study conducted on 65 doctors.

“Booster jabs have proven to be effective in protecting people against the Omicron variant," Yasuko Mori, a professor at Kobe University, said at a news conference that day, mirroring similar reports from studies conducted overseas.

The study marked the first on the efficacy of boosters in increasing the levels of neutralizing antibodies against the Omicron variant in Japanese, she said.

The study was conducted this month on 65 Kobe University Hospital doctors who are between the ages of 20s and 60s and had received booster jabs of the Pfizer vaccine in early December.

The researchers studied neutralizing antibody levels against the Omicron variant, the Delta variant and the original strain of the virus in their bodies.

The researchers also had taken samples from the same 65 doctors, two months after and six months after they received their second jabs.

The researchers compared the neutralizing antibody levels against the Omicron variant, the Delta variant and the original strain of the virus in their bodies against these earlier samples.

Less than a quarter of the doctors had neutralizing antibodies against the Omicron variant in their bodies two months after or six months after receiving second jabs.

Even among those who had them two months after or six months after getting second doses, the levels in their bodies were lower than the levels of neutralizing antibodies against the Delta variant or the original strain in their systems.

However, after the third jabs, all the 65 doctors had neutralizing antibodies against the Omicron variant. In addition, the levels of neutralizing antibodies against the Omicron variant were significantly higher following the boosters in the bodies of the doctors who had them already after the second jabs.

The researchers also found that the boosters were effective in producing neutralizing antibodies against the Delta variant and the original strain of the novel coronavirus.

According to the team, the ability of neutralizing antibodies to prevent infections from the Omicron variant gradually fades over time after a third shot.

“Our regular research will see how long the efficacy of a third jab will last," Mori said at the news conference.

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