Though Pakistani officials said Monday there has been a significant decline in the number of families refusing polio vaccination in the country, almost a half million children did not receive the immunization, Agence France-Presse reports. “The number of refusing families has declined (44 percent) from 80,330 during the first national polio round held in January to 45,122 in October,” according to a joint statement from the WHO, the U.N., and the Pakistani government, the news agency writes. “The success achieved notwithstanding, every unvaccinated child constitutes a major challenge,” Elias Durry, WHO senior coordinator for polio eradication, said, according to the news agency. Shahnaz Wazir Ali, a senior adviser to the prime minister, said, “We need to take adequate steps to ensure that the number of children missed for reasons other than refusals is also brought down,” AFP writes. Polio remains endemic in Afghanistan, Nigeria, and Pakistan, where 30 cases have been recorded so far this year, the news agency notes (10/22).