Syria is currently free of polio, but is consider "at risk". Africa
In 2003 in northern Nigeria – a country which at that time was considered provisionally polio free – a fatwa was issued declaring that the polio vaccine was designed to render children sterile. Subsequently, polio reappeared in Nigeria and spread from there to several other countries. In 2013, nine health workers administering polio vaccine were targeted and killed by gunmen on motorcycles in Kano, but this was the only attack. Local traditional and religious leaders and polio survivors worked to revive the campaign, and Nigeria was removed from the polio-endemic list in September 2015 after more than a year without any cases, only to be restored to the list in 2016 when two cases were detected.Africa was declared free of wild polio in August 2020, although cases of circulating vaccine-derived poliovirus type 2 continue to appear in several countries.A single case of wild polio which was detected in Malawi in February 2022, and another in Mozambique in May 2022 were both of a strain imported from Pakistan and do not affect the African regions wild poliovirus-free certification status. History
The effects of polio have been known since prehistory; Egyptian paintings and carvings depict otherwise healthy people with withered limbs, and young children walking with canes. The first clinical description was provided by the English physician Michael Underwood in 1789, where he refers to polio as "a debility of the lower extremities".
The work of physicians Jakob Heine in 1840 and Karl Oskar Medin in 1890 led to it being known as Heine–Medin disease. The disease was later called infantile paralysis, based on its propensity to affect children. Before the 20th century, polio infections were rarely seen in infants before six months of age, most cases occurring in children six months to four years of age. Poorer sanitation of the time resulted in constant exposure to the virus, which enhanced a natural immunity within the population. In developed countries during the late 19th and early 20th centuries, improvements were made in community sanitation, including better sewage disposal and clean water supplies. These changes drastically increased the proportion of children and adults at risk of paralytic polio infection, by reducing childhood exposure and immunity to the disease.Small localized paralytic polio epidemics began to appear in Europe and the United States around 1900. Outbreaks reached pandemic proportions in Europe, North America, Australia, and New Zealand during the first half of the 20th century. By 1950, the peak age incidence of paralytic poliomyelitis in the United States had shifted from infants to children aged five to nine years, when the risk of paralysis is greater; about one-third of the cases were reported in persons over 15 years of age. Accordingly, the rate of paralysis and death due to polio infection also increased during this time. In the United States, the 1952 polio epidemic became the worst outbreak in the nations history.