thanks to the anti vaccine hysteria (ye, it's the mullahs fault, but a lot of them got the idea from reading the anti vaccine hysteria in the UK papers).
Advisory Committee on Immunization Practices (ACIP) and CDC recommendations are evidence-based and provide public health recommendations to the general public on the basis of the best available epidemiological and scientific data to prevent poliovirus infection. This includes recommendations for travelers visiting countries with WPV circulation in the last 12 months or countries and provinces where they will be in situations with a high risk for exposure to persons with imported poliovirus infection.
Three countries are still endemic for polio (Afghanistan, Nigeria, and Pakistan). Countries where WPV has circulated during the previous 12 months include those endemic countries and those with polio outbreaks or environmental evidence of active WPV circulation during this time (Cameroon, Ethiopia, Equatorial Guinea, Iraq, Israel, Somalia, and Syria). Travelers working in health-care settings, refugee camps, or other humanitarian aid settings in these and neighboring countries might be at particular risk for exposure to WPV.
but there's more:
U.S. clinicians should be aware of possible new vaccination requirements for patients planning travel for >4 weeks to the 10 countries identified by WHO as polio-infected (Figure) (13). Four countries (Cameroon, Equatorial Guinea, Pakistan, and Syria) are now designated as "exporting wild poliovirus." Those countries should "ensure" recent (4–52 weeks before travel) polio boosters among departing residents and long-term travelers (of >4 weeks). An additional six countries (Afghanistan, Ethiopia, Iraq, Israel, Nigeria, and Somalia) are designated as "infected with wild poliovirus." Those countries should "encourage" recent polio vaccination boosters among departing residents and long-term travelers. This list might change when the public health emergency of international concern is reassessed at the end of July, and, for some countries, these measures could extend beyond the 3 months validity of these temporary recommendations.†
so one of the side effects of the Syrian civil war is that you could catch polio if you go to Israel...