Vaccine Effects Lower for Elderly, Smokers

Society Lifestyle

Tokyo, Sept. 21 (Jiji Press)--While Japan plans to start "booster" shots of novel coronavirus vaccines for people who have been inoculated against COVID-19 twice, studies have shown that the efficacy of the vaccines tends to fall among the elderly and people who smoke and drink.

With over half of Japan's population having completed their two shots, the government is looking at the possibility of making vaccinations a prerequisite for relaxing restrictions on activities, so maintaining the efficacy of the inoculations is important.

The National Hospital Organization Utsunomiya Hospital tested 378 staff members who had received the vaccine developed by U.S. drugmaker Pfizer Inc. for their antibody titer, or the amount and strength of neutralizing antibodies, three months after their second shots.

The test showed that the vaccine efficacy decreases with age. Specifically, the median levels of antibody titer in people in their 60s and 70s, and men in their 50s were only about half of those for people in their 20s. For women in their 50s, the levels stood at around 60 pct of those for people aged 20-29. The median levels for people who have not smoked were about 12 pct higher than those for all people tested, while the levels for past and current smokers were lower by some 23 pct and 35 pct, respectively.

"Elderly people may not be able to sufficiently maintain antibodies produced by vaccinations as their immune cells weaken with age," Kumiya Sugiyama, deputy head of the hospital in Utsunomiya, the capital of the eastern prefecture of Tochigi, said, adding, "Many immune cells are in the lungs and directly connected to the immune system of the whole body, so smoking damages the immune cells in the organ, making it difficult (for smokers) to maintain antibody levels."

[Copyright The Jiji Press, Ltd.]

Jiji Press