Wild Polio virus case in Niger and virus isolates in Egypt (sewage) - risk assessment


The World Health Organization (WHO) has reported a wild poliovirus type 1 (WPV1) case in Niger, and in Egypt wild poliovirus type 1 (WPV1) was isolated from sewage samples in the Cairo region.

The case in Niger is the first case in the country since December 2011. Molecular studies have confirmed that the virus was imported into Niger, most likely from Kaduna state, Nigeria. The Government of Niger is carrying out supplementary immunisation activities (SIA) to reach more than five million children with polio vaccine to prevent further spread of the disease.

In Egypt, wild poliovirus type 1 (WPV1) was isolated from sewage samples collected on two dates in December 2012 in two areas of greater Cairo. Virus has been detected in sewage only; no case of paralytic polio has been reported. Molecular studies indicate the virus strains are closely related to virus from northern Sindh, Pakistan. Pakistan is one of three countries worldwide affected by ongoing indigenous transmission of WPV (together with Nigeria and Afghanistan). The isolates were detected through routine environmental surveillance in Egypt that involves regular testing of sewage water from multiple sites. Egypt stopped transmission of indigenous WPV, with its last case in May 2004.

Both events confirm the risk of ongoing international spread of polio virus. WHO assesses the risk of further international spread from Nigeria as high, the risk of spread from Niger as moderate to high, and the risk from Egypt as moderate.

All travellers to the area should be age appropriately vaccinated with polio vaccine. A booster dose of polio vaccine is advised if travelling to an area where exposure to polio virus is a risk.

In Ireland most Irish children (91%) have received three doses of polio vaccine (IPV) by the age of 12 months (Q3 2012 data).

Key points

  • Vaccination
    • All children and adults should be age appropriately vaccinated with polio vaccine according to national immunisation schedule (IPV at 2, 4, 6 months, and a booster dose of polio at 4-5 years of age). Anyone who has missed any, some, or all polio vaccine doses should contact their GP.
    • Before travelling abroad all individuals should have completed an age appropriate course of vaccination against polio. Fully vaccinated persons aged 10 years and over at increased risk of exposure to wild poliovirus should be given a booster dose of Td/IPV (or Tdap/IPV if indicated). An interval of at least 6 months should be left between doses 3 and 4.
  • Acute Flaccid Paralysis (AFP) surveillance
    • Hospital clinicians should maintain vigilance and rapidly investigate and report any cases of acute flaccid paralysis (AFP) in children < 15 years of age (regardless of cause). Stool samples should be sent on all such cases to the NVRL for enteroviral testing (please state “AFP investigation”)
    • Any AFP case (regardless of age) arising in an overseas traveller, or contact of an overseas traveller, from an area where polio transmission is occurring should be urgently investigated and reported.

For more information on the WHO report of the polio outbreak in Niger please click here.
For more information on the situation in Egypt please click here.

For most recent polio vaccination recommendations from the Immunisation Guidelines for Ireland, (NIAC 2010) please click here.

For more information on polio and AFP surveillance please click here.