The struggle to contain the coronavirus ahead of the holiday season has prompted some local leaders to ask residents to embrace a more extreme precaution: wearing masks at home.

Tokyo Gov. Yuriko Koike and her counterparts in three neighboring prefectures on Monday wrote a joint message urging older people and people with underlying health issues — and those living with them — to don masks at home during the New Year break. Some other prefectures, including Fukushima and Niigata, have made similar requests.

Japan is in the grips of a fresh wave of COVID-19 as winter sets in, with daily cases in Tokyo hovering at record levels. Authorities don’t have the power to enforce strict lockdowns and are having difficulty convincing people to stay in, prompting the advice on wearing masks at home to prevent them from infecting vulnerable family members.