"In the UK, the proportion of the population who have antibodies due to vaccination or infection or both is very high, so essentially more people are protected," said Prof Balloux. [size= 10pt]Waning immunity may also be a bigger factor in Europe. Many European countries stuck to giving the two vaccine doses three weeks apart. The UK, controversially at the time, spaced them out further which could lead to a stronger and more durable immune response, say experts.[/size]