Society 19/02/2021

Lockdown during first wave in Spain came too late

Decreeing lockdown a week earlier would have prevented more than 20,000 covid-19 deaths

2 min
View of Passeig de la Bonanova in Barcelona during the total confinement of Catalonia

BarcelonaOfficially, the first wave of covid-19 caused around 28,000 deaths across Spain. Could they have been avoided? A study led by the team of Àlex Arenas, ICREA professor of mathematics and computer engineering at the Universitat Rovira i Virgili in Tarragona, reveals that decreeing total lockdown just a week earlier would have limited mortality to only 5,000 cases. On the other hand, if it had been decreed a week later, the total number of deaths could have shot up to 120,000. The time factor, Arenas says, "is key" when the only measures that can be applied to contain the pandemic are non-pharmacological and the incidence follows an exponential growth curve. In other words, lockdown came too late.

The first lockdown was decreed on 15 March together with the state of alarm. Subsequently, from 29 to 12 April, total lockdown was decreed. From 2 May onwards, the restrictive measures were gradually lifted. During all this time, the measures adopted were physical distance, hand hygiene, the use of face masks and the limitation, more or less intense, of social interactions. Without vaccines or specific drugs, these were the only possible responses to covid-19.

"We have taken the official data from the first wave and, using statistical methods, we have reconstructed both the incidence and the delay in reporting", the mathematician explains. "At the beginning we were not effectively detecting the infection", he continues. Once the reconstruction was done, Arenas' team simulated the different scenarios, mainly lockdown, to establish what would have happened if it had been applied earlier or later. The result is that "losing only one day to apply lockdown" caused "dramatic effects". According to the expert's calculations, moving a week earlier would have reduced the 28,000 deaths to just 5,000. "This data has to help us take better decisions in the future", he says. And postponing lockdown for a week could have caused 120,000 deaths.

A second finding is that even as the curve continued to grow, one of the indicators, the rate of spread (Rt), stagnated or began to slow down before the lockdown was ordered. "People saw it coming", Arenas suggests. A detailed analysis of the consumption of information related to the pandemic, internet traffic, social networks or consultation topics, which grew significantly during the previous days, highlights a "state of population alertness" that prevented the first wave from being worse.

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