Spanish Health Ministry warns that the coronavirus could be spreading in homes

On Monday, Spain recorded its lowest number of new coronavirus infections since the beginning of the crisis – 3,477 in 24 hours, according to Health Minister Salvador Illa. But in most cases – both daily infections and the overall total which was 169,496 as of Monday – there continues to be no clear explanation about the source of contagion.

What is clearer is the number of health workers and police officers who have been affected by the virus. According to Illa, around 25,000 health workers have contracted the disease from work, of whom 31 have died. Meanwhile unions and police associations estimated last week that 14,000 officers had been infected. But for the remaining 130,000 cases there is no clear information about the source of the infection. What’s more, there are no detailed figures on how many senior care residents and care workers have been affected by the virus. Illa, however, has warned of another “important” site of infection: the home.

We think contagion could have happened in the home

Health Minister Salvador Illa

The coronavirus cases identified now correspond approximately to infections that happened between 10 and 15 days ago – the average time between a person getting the disease and experiencing such severe symptoms they need to be taken to the hospital or emergency room, which is when they are included in the Health Ministry’s tally. This means that the infections occurred after the first phase of the lockdown, which was implemented on March 14 after the government declared a state of alarm, and before the total shutdown of all non-essential activity, which came into effect at the end of March.

“Having significantly reduced mobility [under the lockdown], we think contagion could have happened in the home,” said Illa, who added that anyone experiencing symptoms must contact their doctor, take “strict hygienic measures,” and avoid as much as possible contact with the people they live with. The homes “are an important source” of infection, he said.

The situation seems to suggest that “there has been transmission inside and outside of the home and in assistance centers,” says Miquel Porta, professor of preventive medicine and public health at the Autonomous University of Barcelona.

“There has been transmission in the home and in senior residences. Also in essential activities that have continued operating, like health services, supermarkets and so on,” adds José Martínez Olmos, who was general secretary of health under the José Luis Rodríguez Zapatero administration between 2005 and 2011, and now teaches at Andalusia’s Public Health School.

The range of contagion sites is so wide that both experts agree that there continues to be transmission in all areas. Despite this, the number of new cases has fallen to its lowest point in four weeks because “confinement works,” explains Martínez Olmos. That said, Spain saw a record-high number of new infections on March 31, when 9,222 new cases were recorded.

“The transmission chains between March 9 and 15 [many of which went undetected], plus the high transmission in senior residences and health centers explain what has happened these past few weeks,” says Pere Godoy, the president of the Spanish Epidemiology Society.

Joan Ramon Villalbí, from the Barcelona Public Health Agency, agrees that “it is likely that many recent cases are the product of mild cases that were left to self-isolated in their homes when there were no face masks. But we have relatively little information about this,” he explains.

Complaints about the lack of data and poor quality of the figures are common among specialists. The number of coronavirus deaths reported in Spain is not even accurate, given that only people who have been tested for the coronavirus are being included in the official tally. This leaves out individuals with symptoms who die in their homes or at senior residences without ever getting tested.

Last week, the Justice Minister asked civil registries to send the corresponding information on fatalities but it has not yet published the results. Given the lack of data, “it is very important, and not only for the experts, that it be clear that the best and most quantitative understanding [of the outbreak] can only come from the seroprevalence study,” says Porta, in reference to a test that looks at what percentage of the population tests positive for the virus, as measured in blood serum.

It is likely that many recent cases are the product of mild cases that were left to self-isolated in their homes when there were no face masks

Joan Ramon Villalbí, from the Barcelona Public Health Agency

The Health Ministry announced last week that it would begin this seroprevalence study, which is expected to test around 62,000 people from 30,000 homes. The study is being designed by the National Statistics Institute (INE) and the Carlos III Health Institute, but the corresponding protocols have not yet been finalized. What’s known so far is that at least 600 tests will be carried out in each province. According to the technical details, the survey has been organized to detect with 95% accuracy how many people are or have been in contact with the virus. The Health Ministry expects that at least 5% of the sample will test positive for Covid-19. If this is representative of Spain’s entire population, around 2.3 million people could have contracted the coronavirus, which is far more than the 170,000 cases registered as of Monday.

The situation in Spain, where there is a lack of data, is in stark contrast to South Korea, a country with almost the same population as Spain. Despite being one of the first countries hit by the virus after China, South Korea only reported 10,537 cases and 217 deaths on Monday. One of the main reasons South Korea has been able to control the outbreak is the mass testing that it has carried out since the beginning of the crisis. This allowed the country to isolate cases and cut transmission, a process that was helped by cellphone applications that made it easy to follow the spread of the virus and detect infected contacts.

As part of the epidemiological study, the Spanish Health Ministry has asked regional governments to provide a list of facilities, such as hotels and sporting centers, that could be used to house people who test positive for Covid-19, and who are unable to self-isolate in their homes. Villalbí says this strategy is key to stopping coronavirus transmission in the home.

English version by Melissa Kitson.