Polio in China

As of 13 September 2011, nine cases of polio have been reported in the Xinjiang region.  There has been one death.  All of the cases had wild-type polio 1 (WPV-1) which originated from Pakistan.  Xinjiang shares a border with Pakistan where polio is endemic, along with other neighbouring countries, India, Afghanistan and Tajikistan that are also polio-endemic.

Four children between the ages of four months and 2 years were infected in July, data for the other five are unknown but appear to be all infants, including the one fatality.  This is the first outbreak of polio in China since 1999, when an importation from India was identified.  The last indigenous case was in 1994.  An intense surveillance and vaccination programme has been launched in the region in hopes that the spread can be contained.  However, given that paralytic polio occurs in ~1% of polio cases and of that, 5-10% result in death and there were at least four cases of paralysis and one death, it is more than likely that hundreds, if not thousands of cases have gone undetected.

This outbreak demonstrates the vulnerability of populations who are not adequately vaccinated and the relative ease at which an infectious disease can cause an outbreak even in a country previously certified as polio-free.