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Polio Highlight

Some clarifications regarding poliovirus circulation in the Americas

  1. There is no circulation of wild polioviruses in any country of the Americas;
  2. The last wild poliovirus that was isolated in the American Region was in Peru in 1991;
  3. In April 2011, Peru reported a paralytic polio case caused by a Sabin-derived virus;
  4. Active search, specimens collected, and vaccination campaigns in the community were conducted in response to this case;
  5. No evidence of circulation of that virus was found;

PAHO restates its recommendations on strengthening the Acute Flaccid Paralysis (AFP) surveillance system and the evaluation of its indicators at national and sub-national level, and on the identification of high-risk districts and on the appropriate measures to protect the community. The risk of reintroduction of wild polioviruses to the countries of the American Region remains high as long as there is circulation of wild viruses in the world. Just last month the virus was reintroduced into China from Pakistan.


Wild Poliovirus in China and Kenya

We have received information from WHO that underscores the risk of receiving importations even in countries that have been polio-free for a long time. It is a remainder of the importance of maintaining a good surveillance system and very high coverage with OPV in every municipality. (Information available in WHO at 26 August 2011)



  • The Ministry of Public Health, China, has informed WHO that wild poliovirus type 1 (WPV1) has been isolated from four young children, aged between four months and two years, with onset of paralysis between 3 and 19 July 2011.
  • All four cases are from Hotan prefecture, Xinjiang province, western China. 
  • Genetic sequencing has determined that the WPV1 cases found in China are likely to represent an importation from Pakistan. The last WPV case in China was reported in 1999 and was due to an importation from India. The last indigenous polio case occurred in China in 1994.
  • A joint national/international team of epidemiologists and public health experts are on their way to the affected province, to assist in the investigation and planning of response activities. Xinjiang provincial and local public health authorities are currently conducting an epidemiological investigation, including collection of stool specimens from contacts and evaluation of vaccine coverage.  
  • The Ministry of Public Health plans to conduct an initial response vaccination campaign in early September, targeting 4.5 million children aged under 15 years in the immediate outbreak area, and children aged under 5 years in adjacent prefectures. . 
  • In July this year, China hosted an international workshop on inter-regional collaboration in polio eradication in Urumqi, Xinjiang, China.  A key focus of the meeting was the possibility of international spread of polio to polio-free countries in Asia and Europe.
  • The Ministry of Public Health will hold an emergency meeting on the outbreak tomorrow, Saturday 27 August 2011 in Beijing, after which more information will become available.


  • Confirmation was received of a new wild poliovirus type 1 case in Kenya.  The case is a four-year old boy, and onset of paralysis was on 30 July 2011.
  • The case occurred in Nyanza province, western Kenya, near the border with Uganda.
  • Genetic sequencing to determine the origin of this case is ongoing.
  • The most recent WPV found in the greater Horn of Africa area was from Uganda, with onset of paralysis on 15 November 2010.  This was a continuation of the 2009 outbreak in the Turkana region of northern Kenya. 
  • Both Uganda and Kenya conducted supplementary immunization activities (SIAs) recently, on 4 June (in Kenya) and 16 May (in Uganda).
  • An international response team is being deployed this weekend to support the Government of Kenya in the case investigation and the development of an outbreak response plan. Uganda has been informed about the new case. More information will become available as the investigation proceeds.

We are taking advantage of this opportunity to emphasize the last recommendation of the Technical Advisory Group on Immunization (TAG).

During its XIX Meeting in Argentina on July 2011, the TAG concluded that OPV continues to be the vaccine of choice for the American Region as long as there is circulation of wild polioviruses in the world.

Last Updated on Thursday, 01 September 2011 12:20

Chad and the Democratic Republic of the Congo

One third (111) of all polio cases reported so far this year (333) have occurred in endemic countries while two thirds (222) have taken place in re-established or importation countries. Over 50% (175) of all cases come from just two countries: Chad and the Democratic Republic of the Congo.

'More Than A Goal' – Football Club Barcelona Joins the Fight to Eradicate Polio

Football Club Barcelona team up with the Bill & Melinda Gates Foundation to raise awareness and the need of polio eradication.
For a kick-off video and more, visit:

PAHO’s Technical Advisory Group on Vaccine-preventable Diseases (TAG) - Polio recommendations, July 2011

• Countries of the Region of the Americas should continue to use the OPV vaccine until global polio eradication is achieved.

Last Updated on Thursday, 28 July 2011 12:11
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