To the Editor: In their JAMA Classics commentary, Drs Cochi and Kew1 stated that poliovirus type 2 was eradicated in 1999. However, vaccine-derived type 2 poliovirus has been circulating in Nigeria from 2006 to the present, resulting in 103 cases during the period January 1, 2007, to August 12, 2008.2 The re-emergence and continued circulation of this type of poliovirus is not consistent with eradication.