How close are we to regrowth?

Text and data:

Antonio Villarreal

Jesus Escudero

Design and development:

Irene De Pablo

Laura Martin

Carlos Muñoz

Luis Rodriguez

Pablo Narvaez

Data updated to July 17, 2020


Just as a drop of water is able to find the smallest gap in a pipe to cause a leak, the coronavirus takes every opportunity to continue expanding. It does not matter that almost all of us wear masks, wash our hands or maintain an adequate safety distance. As soon as someone stops doing it, the virus will filter through our defenses.

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It is what epidemiologist Michael Osterholm defines as "viral severity." Just like objects fall to the ground if nothing gets in their way, SARS-CoV-2 will continue to infect people as soon as the slightest chance arises.

Therefore – as we have already learned at great cost, human and material – outbreaks are inevitable, as can be seen in the following graph, which we will keep regularly updated, each province is now following its own epidemic curve.

This situation will continue until that long-awaited vaccine appears or we reach sufficient group immunity, which experts place between 40% and 70% of the population, far from the 5% estimated by the national seroprevalence study.

A few weeks after it first appeared in Spain, around March 12, the virus had already managed to spread through the community in all Spanish provinces. Ceuta and Melilla would fall a few days later.

Regrowth is not the problem

The vast majority peaked in the number of reported cases and daily deaths in late March or early April. However, we now look at how regions that then managed to stop contagion bleeding are now in trouble.

Since the end of June they have been the region of Segrià in Lleida, four regions in Huesca, Ordizia in the Basque Country or A Mariña in Lugo, but the general impression is that the draw for this macabre lottery can fall anywhere.

Huesca and Lleida represent the two sides of this story. Both are experiencing new outbreaks of covid-19 derived from a very vulnerable sector of the population: migrant temporary workers who, due to their characteristics, live in common dormitories and for whom it is very difficult to establish isolation measures or trace close contacts, the two essential tools for short-circuit the outbreak.

In Huesca, the incidence accumulated during the last week (average of daily cases reported in the last seven days per 100,000 inhabitants) on June 21 reached 81.57. During the entire pandemic, only one day a higher number was registered in the province, it was on March 29, when the AI ​​reached 92.45 and the days before and after it exceeded 75 incidence points.

Lleida, for its part, started the month of June with an AI over 25 – not negligible, in fact it delayed its access to Phase 2, but controllable – that towards the end of the month and once the state of alarm was over, it shot up coinciding with the outbreak in Huesca, at the autonomous limit of which many of the agricultural farms involved border.

At first it seemed that the situation was more precipitated from the Aragonese side (on June 21 Lleida had an AI of 50 compared to the more than 80 in Huesca) but it soon emerged that the province of Huesca had a little more preparation to face regrowth. Specifically, the ability to perform PCR tests in primary care and to track down possible close contacts of positive cases.

This, together with a very fast action when returning four regions to Phase 2 (just two days after hitting the ceiling) led to better control of the outbreak. In Lleida, however, confinement is currently being discussed.

That there are active sprouts is inevitable, the problem is that they grow to overflow the tracking system

In the Catalan province, on July 2, a cumulative incidence of 225.89 cases was reached in the last seven days, practically double the highest figure recorded during the confinement: on March 23 and 24 it was 115.

Do not be guided only by headlines such as "there are 120 active regrowths", these are inevitable in a context of greater mobility like the current one. The only problem is that these outbreaks grow to a point where primary care is not able to carry out PCR tests on everyone infected, or where contact trackers – in many provinces, scarce – are unable to identify all the suspects.

There's the red line, and it only takes a blink to cross it. At the end of June we were averaging 360 new cases a day and by mid-July the AI ​​had already risen to almost 600 daily.

Sprouts around the world

The case of Spain is not unprecedented, we are simply following in the footsteps of the rest of Western European countries. In Italy, Germany, Belgium, the Netherlands or France the same trend occurs: after a month of May in which the cases fell considerably – as a consequence of strict confinement – in June and July the curve remains flat: they have not returned to go up like then, but SARS-CoV-2 is not going away either.

Added to this is the bad news that comes from other parts of the world. In the United States, the climax has not yet been reached and in mid-July they are registering around 60,000 new cases a day when two weeks earlier they were just over 40,000.

It should not be forgotten either that it is currently the southern winter and the countries of the Southern Hemisphere are suffering the consequences: Australia, which a couple of months ago was counted as one of the success cases against covid-19, has multiplied by four its incidence. The southern African continent, from South Africa to Lesotho, Zimbabwe, Angola, Namibia or Madagascar, is in them. And in South America, except for the honorable exceptions of Paraguay and Chile, all countries are seeing their numbers of infections grow.

In all these cases it would not be necessary to speak of sprouts, because in the South, unfortunately, the first wave is still in full swing.