Key Development: Update on Polio in France Following the Circulation of Wild Poliovirus in Israel and Syria, as of November 12, 2013

In May 2013, Israel reported the isolation of a wild poliovirus type 1 (WPV1) strain in wastewater samples collected in the southern part of the country; this strain was identical to the one that had recently circulated in Pakistan and was also detected in December 2012 in Cairo in environmental samples. This strain was isolated in the stool samples of 42 asymptomatic individuals among nearly a thousand people tested in these same regions, all of whom had been vaccinated exclusively with the injectable polio vaccine (IPV). On October 17, 2013, the WHO reported 22 clustered cases of acute flaccid paralysis that had occurred in Syria since August in the province of Deir Al Zour. As of November 11, 2013, the WHO confirmed that a PVS1 had been isolated in 13 of these 22 cases. Preliminary genetic sequencing results indicate that this is a strain closely related to those that have recently circulated in Pakistan, Egypt, and Israel. In France, the last case of indigenous polio dates back to 1989 and the last imported case to 1995, both involving adults. Extreme vigilance remains necessary, however, by verifying and updating the vaccination status of anyone traveling to a country where WPV is circulating. Furthermore, the risk of a possible reintroduction of poliovirus into France cannot be ruled out, due to the persistence of outbreaks worldwide. While polio vaccination coverage is very high among the youngest age groups (between 99% at age 2 and 90% at age 15), it remains suboptimal among adults (66% on average). The results of a seroprevalence survey conducted in 1998 in the general population showed a proportion of seronegative older individuals close to 20%, with a higher prevalence for serotype 3. The earliest possible identification of the potential reintroduction of a poliovirus into France is now ensured by enhanced surveillance of enteroviruses in humans and the environment, in addition to the mandatory reporting of polio cases.

In summary:

• the risk of reintroduction of a wild poliovirus into France from a country where this type of virus circulates is not zero;

• any traveler who is not up to date on their polio vaccinations and is traveling to a country where wild polioviruses circulate is at risk of infection, however low that risk may be;

• it is therefore necessary to verify and update vaccinations in accordance with the recommendations of the immunization schedule for poliomyelitis: - primary vaccination (mandatory): 1 dose at 2 and 4 months of age, and a booster at 11 months; - boosters (mandatory): at age 6, then between ages 11 and 13; - adult boosters: at ages 25, 45, and 65, then every 10 years starting at age 65.