MADRID (Reuters) – Preliminary results from a nationwide coronavirus antibody study show that about 5% of the overall Spanish population has been affected, the Health Ministry said on Wednesday, adding that results varied widely from region to region.

The study, carried out by the Carlos III institute for health and the National Statistics Institute, began on April 27 and aimed to test 90,000 people across 36,000 households for the presence of antibodies generated to fight off the virus.

The testing should help the government gauge the true extent of the epidemic, taking into account also those who may be immune or resistant to the infection.

(Reporting by Jessica Jones; Editing by Andrei Khalip)