“China vaccinated 4.5 million children and young adults over the last five weeks in the western region of Xinjiang in a fight against polio after the disease paralyzed 17 people and killed one of them, the World Health Organization said,” according to Reuters. This is the first outbreak of polio in China since 1999, “and scientists say the strain originated from Pakistan,” one of four remaining countries where polio is endemic, the news service writes.

“WHO assumes that for every case it finds, there would be 199 others infected with the virus without displaying symptoms,” according to Oliver Rosenbauer, WHO spokesperson for the Global Polio Eradication Initiative in Geneva, Reuters reports. According to Rosenbauer, polio-free countries must maintain high immunization rates and political will to eradicate the disease to reduce the risk of outbreaks, Reuters notes (Tan, 10/18).