Wild-type poliovirus 1 transmission in Israel – what is the risk to Europe?

Published: September 27, 2013

European countries have been officially polio-free since 2002. Concern has been raised in recent months that Europe may be at risk of polio virus importation. Wild-type polio virus 1 (WPV1) has been isolated in sewage and in the faeces of asymptomatic carriers in Israel since February 2013. ECDC conducted a risk assessment of the potential impact of this public health event on the risk of poliovirus importation and re-established circulation into the EU area.

Conclusions
The ECDC risk assessment report concludes that based on the evidence,

• there is a risk of importation and re-establishment of WPV into the EU via a recently infected person shedding the virus, considering the significant population flow from and to countries where WPV is still circulating, as well as the sub-optimal potential for early detection of the virus in both the environment and the population.
• The overall threat posed by poliovirus re-establishment can be considered to be very low in oral polio virus (OPV) vaccinees for both poliovirus infection and disease; moderate in inactivated polio vaccine (IPV)-only cohorts for poliovirus infection and low for disease; and high in low or unvaccinated groups for poliovirus infection and moderate for disease. The highest level of risk is posed by the proximity of clustered un- or under-immunised population groups to large populations vaccinated using inactivated polio vaccine only schemes. Sub-optimal hygiene and crowded living conditions may also play a role in facilitating the spread of infection.

In Ireland IPV vaccine has been used routinely since 2001. Prior to 2001 OPV was the vaccine used routinely and for booster doses among travellers to polio risk areas. All children are recommended IPV as part of combined vaccines at 2,4,6 months and a booster  (‘4-in-1’ vaccine) at 4-5 years of age.

Most, but not all, children in Ireland are age appropriately vaccinated. Current uptake of three doses of IPV vaccine in Irish children at 12 months is 91% and at 24 months 95% (Immunisation Uptake Q1 2013 report). Estimated uptake of four doses through the school immunisation programme (4-5 years of age) is 86% and among children vaccinated by GPs is 74%. 

Recommendations

• Parents should ensure their children’s vaccinations are up to date. Children who have missed their recommended doses should contact their GP to obtain missed vaccinations.
• Children coming from other countries who have received four IPV containing vaccines before their fourth birthday as part of their primary course should receive the 4 in 1 booster (i.e. a fifth dose of IPV) ≥ 6 months after the previous dose.
• All travellers to and from poliovirus-affected areas are advised to be fully vaccinated against polio.  Fully vaccinated persons aged 10 years and over travelling to endemic countries should be given a single dose of Tdap/IPV.
  At-risk persons include those:
  • travelling to countries or areas where poliomyelitis is epidemic or endemic
  • in contact with patients who may be excreting wild poliovirus
  • in contact with specimens that may contain wild poliovirus
• Clinicians should immediately report to the medical officer of health and investigate any suspect polio cases (acute flaccid paralysis/meningitis) among travellers to polio endemic areas

Further information
ECDC risk assessment report
National Immunisation Guidelines – Polio chapter
Polio (HPSC website)