WHO says new flu "unstoppable"

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - Saying the new H1N1 virus is "unstoppable", the World Health Organization gave drug makers a full go-ahead to manufacture vaccines against the pandemic influenza strain on Monday and said healthcare workers should be the first to get one.

Every country will need to vaccinate citizens against the swine flu virus and must choose who else would get priority after nurses, doctors and technicians, said Dr. Marie-Paule Kieny, WHO director of the Initiative for Vaccine Research.

Several reports showed the new virus attacks people differently than seasonal flu -- affecting younger people, the severely obese and seemingly healthy adults, and causing disease deep in the lungs.