Polio may be gone, but keeping the Region free of polio remains critical even since certification. The Region must maintain a vigilant AFP surveillance system and effective national immunization programmes that can reach all children. The re-introduction or importation of wild poliovirus into the Region continues to be a threat as long as the virus is circulating anywhere in the world.

2004 was a year of successes and challenges for the Global Polio Eradication Initiative. Intensified eradication activities were making good progress in Asia. An increase in the quality and quantity of poliomyelitis campaigns in Afghanistan, India and Pakistan reduced the geographical distribution of wild-type poliovirus in those countries, with altogether just 141 cases reported in 2004 compared with 336 cases in 2003. In Egypt, poliovirus transmission fell to its lowest level ever as the quality of poliomyelitis campaigns improved further.

In contrast, sub-Saharan Africa experienced epidemic polio as a result of a suspension (from August 2003 to 31 July 2004) of immunization against the disease in the state of Kano, Nigeria, and low routine immunization coverage in some neighbouring countries. Consequently, reported cases of polio in Niger and Nigeria increased to 807 in 2004 compared with 325 in 2003. Since this halt in vaccination, importations of wild polioviruses have occurred in 17 previously polio-free countries. In six of these countries (Burkina Faso, Central African Republic, Chad, Côte d’Ivoire, Mali and the Sudan) endemic transmission of the imported polioviruses was re-established. Poliovirus was most recently imported into Yemen and Indonesia, resulting in outbreaks with almost 500 cases and 300 cases respectively (as reported in early November 2005). Further details and regular updates on the situation of the Global Polio Eradication Initiative can be found.

A long time before these current events, the Western Pacific Region had already received a warning of the danger of importation of poliovirus in 1999 when preparing for Regional certification. A 16-month-old boy became paralysed on 11 October in Qinghai Province, China.

At that time, genetic examination of the virus showed that it was quite different from any seen before in China, but similar to those found in the Indian subcontinent. All evidence therefore suggested that the virus had been imported. The case was detected so quickly and a follow-up immunization response conducted so effectively that the experience provided confidence in the systems of surveillance and immunization used throughout the Region.

Maintaining polio-free status also means public health facilities in the Region and around the world must identify where wild polioviruses are stored. This is laboratory containment. Once global polio transmission is completely interrupted, the laboratories represent the only source of wild poliovirus infection. WHO is leading an effort to catalogue, safely store or destroy existing stocks of wild poliovirus and potentially infectious materials.