Some European countries may be at risk for polio, as refugees from Syria -- where a civil war has led to decreased vaccination rates and an outbreak of the paralyzing disease -- flee to Europe, experts warn.
The experts, Martin Eichner, a professor at the University of Tübingen, and Stefan Brockmann, of the Reutlingen Regional Public Health Office in Germany, explained in an editorial in The Lancet that most European countries vaccinate against polio using the inactivated polio vaccine, which does not provide full protection from infection by the polio virus.
Another kind of vaccine, the oral polio vaccination, provides "high protection against acquisition and spreading of the infection, but this vaccine was discontinued in Europe because of rare cases of vaccination-related acute flaccid paralysis," they wrote in the editorial. "Only some of the European Union member states still allow its use and none has a stockpile of oral polio vaccines."
In countries where there are low vaccination rates, herd immunity may not be enough to prevent polio from spreading, they noted. Countries that could be particularly at risk include Bosnia and Herzegovina, Ukraine, and Austria.
In addition, because not everyone infected by the wild-type poliovirus 1 will actually develop paralysis -- only about 1 in 200 people will develop acute flaccid paralysis -- it could take as long as a year before a case of symptomatic polio arises, and people are made aware of an outbreak.
Therefore, it may not be enough to recommend only vaccinating Syrian refugees -- which is the official recommendation by the European Centre for Disease Prevention and Control -- to prevent polio from appearing in Europe, the experts said.
The United Nations confirmed 10 cases of polio -- all in babies and toddlers who were "under-immunized" in northeast Syria last week; it's the first time the disease has been confirmed in the country in more than 14 years, the Associated Press reported. Meanwhile, another 12 cases are still awaiting lab confirmation.
The World Health Organization has already warned that polio could pose a threat to other countries in the Middle East; the virus can be spread through contaminated food and water, according to Reuters.