At least 24 people nationwide have died of influenza-related diseases this month, according to a survey conducted by Kyodo News.

Of the 24, 20 were elderly people who died of pneumonia or bronchitis at welfare facilities, including nursing homes in Iwate, Miyagi, Niigata, Gunma and Saitama prefectures, according to the survey released Wednesday.

On the same day, the Health and Welfare Ministry instructed prefectural governments to step up vaccination of residents at such facilities and to take other preventive measures.

Managers of such facilities have already been urged by some local governments to ensure their residents are getting proper care, including well-balanced meals.

The survey found that 11 people, the largest number of flu victims, died in Miyagi Prefecture. At a nursing facility in Shiroishi, south of Sendai, seven residents between the ages of 76 and 88 died of pneumonia believed to be caused by influenza around Jan. 19.

In Niigata Prefecture, five elderly women at a welfare center have died of influenza. The women, whose ages ranged from 86 to 93, died between Jan. 14 and Monday, according to the survey. There are 25 other people at the center in the town of Kakizaki who are believed to have caught the flu.