The effect of new schedules of immunisation on humoral and intestinal immunity to poliovirus and implications for the polio end game
Poliomyelitis became a serious public health issue for higher income countries in the twentieth century. This led to the development of vaccines in the mid-1950s and the eventual control and elimination of the disease by the 1970s. It remained common in lower and middle income countries despite the use of vaccine; this was probably partly to do with the epidemiology and pathogenesis of the disease and partly to problems of delivering vaccines in tropical areas with poor infrastructure. The Global Polio Eradication Initiative began after the development of newer and more effective strategies for vaccinating in tropical countries and as a response to resolution WHA 41–28 of the World Health Assembly in 1988 which committed WHO to eradication. The initial target date was 2000, a deadline that was clearly not met. By 2016 however there were only three member states that had never interrupted endemic transmission (Nigeria, Afghanistan and Pakistan) and the prospects for eradication are very good with less than fifty cases world-wide in 2016.