Children under 10 are set to be offered polio vaccine boosters amid a rise in the amount of the virus detected in London's sewage works.
Health authorities plan to give children the shots regardless of where they are on their polio vaccine schedule, in a bid to prevent what would be the first community outbreak of the disease in the UK since the 1970s.
Polio can cause symptoms including a high temperature, tiredness, headaches, vomiting and muscle pain. In rare and extreme cases it can lead to more serious symptoms that affect the brain and nerves.