Results from the latest stage of a nationwide antibody study show some 9.9 per cent of Spain's population, or about 4.7 million people, have been exposed to the coronavirus, health officials say.

The study found the virus' prevalence had increased during the second wave of infections in the summer and autumn. It is also much higher than the number of confirmed cases in Spain, of just over 1.75 million.

First results of the study that were published in July after testing nearly 70,000 people across Spain in April-June showed a prevalence rate of just over 5pc.