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REUTERS/Hannah Beier/File Photo/File Photo A vial of the Pfizer-BioNTech coronavirus disease (COVID-19) booster vaccine targeting BA.4 and BA.5 Omicron sub variants is pictured at Skippack Pharmacy in Schwenksville, Pennsylvania, U.S., September 8, 2022.
The Yomiuri Shimbun
15:47 JST, May 12, 2021
About 90% of Japanese people who received two doses of Pfizer Inc.’s vaccine against COVID-19 developed antibodies that could prevent the onset of the disease from novel coronavirus variants as well as the original virus, a study by Yokohama City University has found.
As coronavirus variants are spreading in Japan, the research highlights the importance of promoting the ongoing vaccination program.
In the study, blood samples were collected from 105 doctors and nurses, aged 24 to 62, who were vaccinated with the Pfizer vaccine in March and April. The vaccine is normally given in two doses on two separate occasions. The samples were taken before and after the inoculations.
Examination of the antibodies contained in blood a week after the second inoculation showed that 99% of the participants had developed antibodies that are likely to have a sufficient preventive effect against the original form of the novel coronavirus. High efficacy was confirmed for variants as well, with 94% of the participants found to have developed antibodies effective against the British variant that is spreading in the nation, 90% for the South African variant and 97% for the Indian variant.
The first dose on its own was found to offer a more limited amount of protection. Examination two weeks after the first inoculation found that only 57% of participants had antibodies of sufficient preventive effect against the original virus, along with 18% for the British variant, 21% for the South African variant and 37% for the Indian variant.
Yokohama City University Prof. Takeharu Yamanaka, a member of the research team, said, “If people are properly vaccinated with two doses, we think sufficient preventive effect can be expected for variants as well.”
The team will continue to study the duration of the vaccine’s effectiveness and the effectiveness of other vaccines.
“The research shows a possibility that the vaccine can also be effective against variants, a factor that may help promote the vaccination program,” said Jikei University Prof. Mitsuyoshi Urashima, who specializes in preventive medicine. “However, the duration of the vaccine’s effectiveness is unknown, and the effectiveness could deteriorate with further mutations of the virus. It is necessary to carefully examine the matter.”
