Wastewater surveillance has uncovered likely local spread of poliovirus in London, the New York Times reports. It adds that officials have deemed this a national incident but say no cases have been tied to these findings.
Such surveillance, the Times notes, generally finds one or two instances of poliovirus a year. The Telegraph reports that officials this year detected poliovirus in wastewater from North and East London in February, which it notes normally would not have raise an alarm except that a related strain was then detected in April and May.
According to the Times, poliovirus was likely introduced to London around the beginning of the year, probably from someone entering the country. It adds that the virus uncovered is similar to the weakened one used in oral polio vaccines in some parts of the world, but, as the Telegraph adds, has developed mutations that make it resemble wild-type virus.
The UK Health Security Agency adds that the last wild polio case in the UK was in 1984 and the country was deemed polio-free in 2003. While there is high vaccine coverage across the UK for polio — using injected inactivated poliovirus, the Times notes — uptake among children has been lower.