Alarm of Circulating Wild Poliovirus and Of Vaccine-Derived Poliovirus in Middle East Countries as a Potential Risk for Re- Emerging of Polio in Iran

Poliomyelitis is a highly infectious viral disease which is mainly transmitted via contaminated food and drinking water by human feces, especially in situations of poor hygiene and sanitation (1). This disease is caused by 3 types of wild poliovirus (WPV) (types 1, 2 and 3), and immunity against one type does not create immunity against other types. In our country according National Immunization Program (2), inoculation 6 doses of oral polio vaccine (OPV) induce immunity for long time against poliomyelitis. The polio eradication was a largest public health innovation is organized by the World Health Organization (WHO), and enhanced routine immunization, adequate response to outbreaks and effective surveillance are the main strategies to reach this goal (3). The last laboratory-confirmed wild polio case in Iran was reported in 1997. From 1998 to 2000, cases were imported from Pakistan/Afghanistan of wild virus circulation. The last case was an imported case from Afghanistan in December 2000 and the circulation of wild poliovirus was stopped in December 2000 and Iran is known as a polio free country from 2001 (4). According WHO report up to 2017, WPV transmission was disrupted in all countries except Afghanistan, Pakistan and Nigeria (5). Although the AFP surveillance in Iran reached to high level and gained the polio-free certification through active surveillance (6), but the role of neighboring countries which can interrupted our achievement should not be ignored. In the following we discuss a bout situation of wild WPV transmission in our neighboring countries.