COVID-19 booster shots will be provided for medical personnel by year-end and for older people in the new year, vaccine chief Taro Kono announced Tuesday.

Japan is one of several countries that are rushing to procure and distribute supplementary doses amid mounting evidence that the antibodies provided by initial shots decline over time.

While scientists generally agree on the importance of booster shots for older people and the immunocompromised, some world-leading experts have said they do not see a need for a booster yet, arguing that the vaccines are still working well enough to prevent serious illness and death. The World Health Organization has also been calling on rich countries to refrain from rolling out booster shots and to instead give much-needed vaccines to poorer nations.