Reply to ‘Apropos “Seroprevalence of Antipolio Antibodies among Children <15 Years of Age in Border Provinces in China”'

We acknowledge the letter of [Arya and Agarwal][1] ([1][2]). Children <5 years of age, particularly children <1 year of age, are most vulnerable to wild poliovirus (WPV). However, some countries with no WPV transmission for a long period of time and relatively low levels of vaccination coverage have