The number of confirmed coronavirus cases in all of Spain is now at nearly 190,000. The figure, updated on a daily basis by the Health Ministry, includes everyone who has tested positive for the virus. But there is another data set that helps give an idea of the dimension of the pandemic in Spain: the number of possible cases.

These include people who have not been given any kind of test, but whose symptoms correspond to a patient who is suffering from the Covid-19 disease caused by the coronavirus. The 10 of Spain’s 17 Spanish regions who are tracking this data have detected at least 419,000 possible cases, according to the information that EL PAÍS has compiled. Madrid and Catalonia account for 73% of them.

The Health Ministry defines possible cases as patients who have a mild acute respiratory infection but have not been given any kind of test

The Health Ministry defines possible cases as patients who have a mild acute respiratory infection but have not been given any kind of test, whether it be the more reliable PCR test or a rapid test used to detect antibodies. These tests are prioritized for the more serious cases who require hospital treatment and personnel from essential services, such as health workers.

In a situation such as the current one, where there is transmission of the virus in the community, primary healthcare centers consider patients with mild acute respiratory infections to be possible cases, without carrying out any kind of test.

The Health Ministry protocols for dealing with these cases were updated on April 11, and detail how such cases should be tracked – whether by telephone, or directly in primary healthcare centers. Those diagnosed as possible cases have to stay isolated in their homes for at least two weeks, while healthcare centers carry out a check-up via telephone after 24 and then 48 hours to check whether the symptoms continue to be mild. If they get worse, or the patient is considered to be within a risk group, they are taken to hospital where, in principle, they are subject to a test.

The number of possible cases is proving of great importance in terms of how the regions are responding to the virus

The figure of possible cases varies faster than that of confirmed cases, given that it depends on a diagnosis that may be made over the phone. This is well reflected in the figures from the Madrid region: the possible active cases (those that are still being monitored) were 45,000 on April 7, and after 10 days, by Thursday, they had fallen to 21,164.

The number of possible cases is proving of great importance in terms of how the regions are responding to the virus. “This activity from primary healthcare has been fundamental until now for early detection [of cases], for appropriate care, isolation and home monitoring or referral to other levels of care,” explains Rafa Cofiño, the general director of Public Health in the northern Spanish region of Asturias. And it will continue to be important “in the new transition phase of the pandemic, when we will have to be very strict with early detection and the study of contacts.”

Ildefonso Hernández, the spokesperson for the Spanish Public Health Society (Sespas), agrees that monitoring possible cases will be decisive in the coming stages of the pandemic. “During the exit phase not all territories – rural areas, for example – will have the same diagnostic capabilities in order to identify a case,” he explains.

Identifying a coronavirus case via PCR testing, for example, requires a microbiology laboratory with specialized equipment, something that small hospitals lack. “Imagine that someone calls from their home in Bielsa or any other isolated place, they go to the doctor, they have compatible symptoms and they have had contact with a case,” Hernández explains. “They can carry out a first antibody test, and that comes back negative. But if they return in a few days and the symptoms continue, it is very reasonable to consider it a possible case. It’s very likely to be Covid-19.”

Every Friday, Spain’s 17 regions must send a weekly summary of possible cases to the central government. In Spain, healthcare systems are devolved to the regions, and work independently from one another. The lack of coordination in terms of the collection of the data means that not all healthcare systems are collecting the information in the same way, something that, Hernández explains, may depend on the capacity of primary healthcare doctors to send reports or because this reporting has started later in some territories.

Unpublished figures

Andalusia, Galicia and Valencia are not making this figure public. Castilla y León, meanwhile, has been among the first regions to publish a daily figure of cases diagnosed at primary healthcare centers: there are 38,444 people with compatible symptoms, more than 44,000 total cases so far, and the curve has begun to flatten. Extremadura and Asturias are also updating the data on their webpages on a daily basis.

In the Basque Country, these possible cases are tracked via a cellphone application. Until this Thursday, 3,502 people reported possible symptoms, while 615 are being monitored by the application itself, and are being considered possible cases.

In the Madrid region, monitoring is being carried out via primary healthcare services, with a current registration of around 26,164 people. In Catalonia, a change in criteria of the collection and distribution of data has seen the number of possible cases included in the daily report. On Thursday, the figure for the northeastern Spanish region was 55,195 people.

As well as monitoring the number of possible cases, there are also regions, such as Asturias, that are monitoring the contacts of confirmed Covid-19 cases. Castilla-La Mancha, for example, is tracking such contacts. Until now, more than 20,000 close contacts have been identified, and they have been advised to spend 14 days in quarantine. In Murcia, via the network of local health centers, more than 26,000 people have been identified as close contacts of positive cases since the crisis began.

The objective is to get an idea of the circle of contacts of each person with coronavirus in order to understand the reach of the epidemic. The contacts are usually the carers of people with symptoms, as well as the partners or close family members who have been in the same place while the person in question presented symptoms, and have been at a distance of under two meters for more than 15 minutes. All of these contacts also have to isolate at home for a two-week period.

English version by Simon Hunter.