21 Feb 2018

Polio: Public Health Emergency of International Concern

An update on the polio Public Health Emergency of International Concern (PHEIC) Polio: Public Health Emergency of International Concern

The sixteenth meeting of the Emergency Committee (EC) under International Health Regulations (IHR) 2005 was convened on 7 February 2018, to review the data on wild poliovirus (WPV) and circulating vaccine derived polioviruses (cVDPV). The EC agreed that the risk of international spread of poliovirus continues to constitute a Public Health Emergency of International Concern (PHEIC). Temporary Recommendations (IHR 2005), to reduce the risk of international spread of poliovirus, were extended for a further three months [1].

The full Statement of the Sixteenth IHR Emergency Committee is available from the World Health Organization.

Wild polio type 1 (WPV1): infected countries (Afghanistan, Pakistan and Nigeria)

During 2017, the number of cases of WPV1 fell to an all-time low; in Afghanistan and Pakistan, efforts to target high risk populations (particularly those living in the areas that border the two countries) have been undertaken. Only eight cases were reported in Pakistan in 2017 (with no cases reported so far in 2018) whereas Afghanistan reported 14 cases in 2017 with a further three cases to date in 2018. The polio program in Afghanistan continues to be challenged by security issues, difficulties in reaching inaccessible children and those who missed vaccination.

Although now 16 months since the detection of WPV in Nigeria, vaccination coverage is low, particularly in the high-risk areas of northern Nigeria (Borno state remains inaccessible) and the possibility of undetected polio virus transmission cannot be ruled out.

The risk of international spread from Nigeria to other countries in the region (i.e. the Lake Chad basin countries) or further afield in sub-Saharan Africa, remains substantial.

There has been no international spread of WPV since November 2017 [1].

Vaccine derived poliovirus (VDPV)

Rarely, where a population is under-immunised, the live virus present in oral polio vaccine can mutate and spread causing outbreaks of circulating vaccine derived poliovirus (cVDPV) [2]. Outbreaks of cVDPV pose a risk for international spread [1].

Democratic Republic of Congo continues to be affected by cVDPV (particularly Tanganyika Province) [1]. Syrian Arab Republic continued to report cVDPV through 2017, but has not reported cases to date in 2018 [3]. Ongoing circulation of cVDPV highlights gaps in the polio eradication programme in hard to reach populations of these countries.

As it is more than 16 months since the last case of cVPVD2 in Pakistan, the country no longer meets the criteria for a cVDPV2 country, but remains vulnerable to outbreaks [1].

IHR Temporary Recommendation categories

States infected with WPV1, cVDPV1 or cVDPV3 with the potential risk of international spread:

  • Afghanistan
  • Nigeria
  • Pakistan

These countries have a certificate requirement for polio vaccination under IHR (2005). Please refer to Country Information Pages.

States infected with cVDPV2, with potential risk of international spread

  • DR Congo*
  • Nigeria
  • Syria*
*There is no certificate requirement under IHR (2005) for these countries. Travellers are, however, encouraged to carry proof of polio vaccination.

States no longer infected by WPV1 or cVDPV, but which remain vulnerable to re-infection by WPV or cVDPV:

  • Cameroon
  • Central African Republic
  • Chad
  • Niger

Guinea last reported cVDPV case on 14 December 2015 and Lao People's Democratic Republic last reported cVDPV on 11 January 2016 [3]. The polio vaccine recommendation for these countries is unchanged - see our Country Information pages.


In addition to the countries detailed in this report, the Global Polio Eradication Initiative highlight the following countries to be no longer polio-virus infected, but at high risk of outbreaks [3]:

  • Ethiopia
  • Equatorial Guinea
  • Iraq
  • Kenya
  • Liberia
  • Madagascar
  • Myanmar
  • Sierra Leone
  • Somalia
  • South Sudan
  • Ukraine

For these countries, NaTHNaC recommends a booster dose of a polio-containing vaccine for those who have not received a dose within the previous 10 years travelling to these countries see our Country Information pages.

The polio status of countries is reviewed by WHO on a regular basis and polio vaccination recommendations are subject to change.

Advice for travellers

Polio is transmitted via the faecal-oral route, either by exposure to water contaminated by infected human faeces, or by person to person contact. You should practise strict food, water and personal hygiene. Independent of your destination, you should complete a primary vaccination course for polio according to the UK schedule. Travellers are encouraged to carry documentary evidence of their polio vaccination status. An International Certificate of Vaccination or Prophylaxis is required by some countries see our Country Information pages for country specific information.

Advice for health professionals

All travellers regardless of destination should be up to date with routine vaccination courses and boosters as recommended in the UK. See our Country Information pages for country specific recommendations and certificate requirements.

For specific outbreak information, check our Outbreak Surveillance. The polio status of countries is reviewed by WHO on a regular basis and polio vaccination recommendations are subject to change.


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