The Bangladeshi government started on Sunday the vaccination of 21 million children under 5 years against poliomyelitis, the disease resurfacing after 5 years. Health and Family Welfare Minister Dr Khandoker Mosharraf Hossain inaugurated the 13th immunization day and said Bangladesh was made "polio-free" through observing 12 national immunization days. "This immunization day has been necessitated by the fact that Rahima of Chandpur district has been affected with polio virus after Bangladesh has enjoyed polio-free status for 5 years and 8 months," he added. The 2 doses of the vaccine will be administered on May 13 and June 11. Golam Kibria, spokesman of the Ministry of Health and Family Welfare, said 600,000 volunteers at 120,000 centers will participate in the vaccination process. The volunteers will then go house to house after 4 days to check any drop out of children of the age group. The campaign will target even the most remote villages and health workers will also administer vaccines at airports, ports and land ports. The country's efforts to escape the virus seemed to be in vain when a 9-year-old girl at Chandpur was found to be infected on January 23 this year. The virus invades the nervous system and can cause paralysis in a few hours, especially in the legs. One in 200 infections leads to irreversible paralysis. Amongst those paralyzed, 5%-10% die when their breathing muscles become immobilized.