Weekly distribution of AFP cases <15 years of age by classification in 2011 and 2012 in Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China.

<p>Note: VDPV, vaccine-derived poliovirus; AFP, acute flaccid paralysis.</p

Rounds, dates, target population, and numbers of persons immunized for SIAs by province, 2012.

<p>Rounds, dates, target population, and numbers of persons immunized for SIAs by province, 2012.</p

Antibody seropositivity of type I, type Π, and type by age group in Ngawa County, Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China, 2012.

<p>Antibody seropositivity of type I, type Π, and type by age group in Ngawa County, Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China, 2012.</p

Descriptive characteristics of case patients and close contacts in an outbreak of type Π cVDPVs in Ngawa County, Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China, August 2011–February 2012.

<p>Descriptive characteristics of case patients and close contacts in an outbreak of type Π cVDPVs in Ngawa County, Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China, August 2011–February 2012.</p