Transmission of poliovirus occurs through contact with the faeces or respiratory secretions of people infected. Those infected can discharge the virus for up to six weeks in faeces and two weeks in saliva. Cases are most infectious immediately before, and one to two weeks after the onset of paralytic disease. The incubation period of poliomyelitis ranges from three to 21 days.
Information for the public can be found on the NHS inform website.
Data and surveillance
Before the introduction of the polio vaccine, epidemics of poliomyelitis were common and up to 8,000 cases of paralytic poliomyelitis could be reported in the UK every year. Following the introduction of the vaccine, the number of cases fell rapidly and the last UK case of poliomyelitis caused by wild polio virus was in 1984. Since then, up to 1993, cases have been acquired outwith the UK, but polio is now considered to be eliminated in the UK.
Poliovirus is targeted by the World Health Organisation (WHO) for eradication and, due to the efforts of countries worldwide, polio is now eliminated from four of the six WHO regions. There are a number of countries at risk of re-introduction, but the only endemic countries that haven't stopped transmission of polio are:
Immunisation against polio is the most effective method of prevention and has been part of the routine schedule since 1956. Polio vaccine is still included in the UK childhood immunisation schedule, with routine primary vaccination recommended at eight, 12 and 16 weeks of age, followed by a booster dose from age three years four months and a further booster between 13 to 18 years. Altogether, five doses of polio vaccine are administered in the childhood immunisation schedule.