Polio is spreading in Britain for the first time in nearly 40 years, health officials have warned, as they declared a national incident, and urged people to make sure they are vaccinated.
Without having read further I’d suggest it’s to do with arrivals from places that aren’t fully vaccinated…..
The UK Health and Security Agency (UKHSA) said that a polio virus had been detected in sewage from North and East London in February.
Health experts believe the virus was probably imported from an individual who had recently been given an oral polio vaccine abroad, possibly in countries such as Nigeria, Pakistan or Afghanistan where outbreaks are still common.
Ahh…..it’s actually vaccine derived, is it?