The study by the Carlos III Health Institute also showed an increasing number of young people with Covid-19 with most new cases now in the 15-29 age bracket.
Two out of every 10 cases have been adolescents or young adults since Spain began to ease its lockdown rules on May 10, the report says.
Forty percent of 25,600 cases in the report were said to be people under the age of 40.
And the average age of Covid-19 patients has fallen to 48 compared to age 60 back in April, according to the survey ‘Covid-19 Situation in Spain’ based on information given by regional authorities.
The changes in the coronavirus patterns in Spain show a huge number of asymptomatic cases.
The report says 55% of cases have never had any symptoms, El Pais reports.
Thirty-seven percent of patients had no idea where they contracted coronavirus but one in four infections happened at home, the survey said.
Almost half of patients were unaware they had been in contact with someone with the disease – but the figure differed among the regions.
In Catalonia, this statistic was said to be as high as three in four cases.
In the Basque region the figure was 11.9% and in Andalusia, the Canary Islands and Aragon it was found to be 20%.
Molina Cabrillana, the spokesperson of the Spanish Association of Preventive Medicine, Public Health and Hygiene, said: “The current situation in Catalonia is bad.
“There is community transmission.”