Polio eradication: surveillance implications for the United Kingdom.
The requirements for certification of elimination of wild virus poliomyelitis will pose particular problems for some industrialized countries, such as the United Kingdom, where there has been no case detected for at least a decade. Systems of surveillance of poliomyelitis have been reviewed and potential weaknesses identified. When oral polio vaccine is routinely used, the rate of vaccine-associated cases provides an indication of the likelihood that if they occurred, wild virus cases would be detected. Acute flaccid paralysis surveillance was done for 3 years, but rates were lower than reported elsewhere and were accepted for certification purposes. Alternative techniques, such as surveillance of polioviruses, either in clinical samples or from the environment, may be developed in such countries. The ability to identify enteroviruses and to distinguish between wild and vaccine strains of polioviruses will give assurance that silent transmission of wild viruses is unlikely.