Scientists will confirm that the second of the three strains of the polio virus has been wiped out. Picture: James Akena/Reuters/ANA

London - Experts are celebrating a major victory for vaccination, with officials expected to announce a key breakthrough in the war against polio.

Scientists will confirm that the second of the three strains of the polio virus has been wiped out.

The eradication of "wild polio virus type 3" – known as "WPV3" – leaves only one polio strain left in circulation. It is only the third virus to be eradicated in history, after smallpox was defeated in 1980 and wild polio virus type 2 (WPV2) in 2015.

Dr Doug Brown, of the British Society for Immunology, said: "The global eradication of WPV3 represents a tremendous step forward in the fight against polio and it means that only type 1 of the wild virus is still circulating and causing infections.

"Vaccination is one of the safest and most effective methods we have to save lives and stop the spread of disease. According to the World Health Organisation, more than 18 million people have been saved from paralysis thanks to the global vaccination efforts against polio."

Polio – which is extremely contagious – is still part of many childhood vaccination programmes.

Before a vaccine was introduced in the 1950s, up to 8 000 children were paralysed with polio in the UK each year and up to 750 died. Dr Charlie Weller, head of vaccines at the Wellcome Trust, said British parents had forgotten the horror of polio and other preventable diseases.

"Like many other people, I grew up in an environment where I didn’t see polio, rotavirus or diphtheria. Complacency comes about when you don’t remember."

Daily Mail