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Cell phone location data show reduction in social isolation in Brazil

by ace
Cell phone location data show reduction in social isolation in Brazil

Contrary to the recommendations of social isolation of the Ministry of Health and the World Health Organization, to contain the advancement of the coronavirus, Brazilians are leaving more than home since the end of March.

All states, in addition to the Federal District, recorded an increase in people on the streets in recent days, compared to previous weeks.

The data are from a survey carried out by In Loco, a technology company that uses data sent by partner applications to measure users' displacements.

Currently, In Loco has a partnership with the city of Recife to monitor the displacement of around 700 thousand cell phones in the capital of Pernambuco. In addition, the data are also used by infectious disease physician Julio Croda, professor at the Federal University of Mato Grosso do Sul (UFMS) and researcher at the Oswaldo Cruz Foundation (Fiocruz).

In Loco claims that data collection is only done with the permission of app users. In addition, the company says it does not pass on information such as name, ID or CPF.

To monitor displacement, In Loco uses GPS, Wi-Fi signals, Bluetooth and telephony. The company says it has real-time location information on 60 million smartphones in Brazil.

Five weeks were considered, from March 3 to April 6. During this period, there was an increase in isolation during the first 4 weeks, as shown in the table below:

Isolation rate in states in recent weeks

March 3-9 March 10-16, March 17-23 March 24-30, March 31 – April 6 Acre 25.18% 30.56% 43.75% 51.48% 48.66% Alagoas 26 , 56% 32.29% 43.69% 55.55% 51.11% Amapá 26.04% 31.55% 47.56% 55.94% 53.31% Amazonas 25.17% 30.37% 40 , 48% 50.98% 50.32% Bahia 25.5% 30.67% 43.49% 55.17% 51.28% Ceará 28.92% 34.72% 49.72% 59.71% 55 , 6% Distrito Federal 33.08% 36% 51.84% 61.18% 57.98% Espírito Santo 27.35% 31.61% 45.62% 55.32% 52.43% Goiás 32.74% 40.21% 53% 61.66% 58.44% Maranhão 29.2% 34.51% 45.01% 55.67% 53.82% Mato Grosso 23.44% 28.69% 40.33% 51 , 13% 46.98% Mato Grosso do Sul 22.41% 27.57% 41.91% 53.19% 47.59% Minas Gerais 25.62% 29.77% 43.88% 54.93% 51 , 52% Para 27.93% 33.37% 42.8% 52.20% 50.54% Paraíba 27.14% 33.08% 45% 56.75% 52.94% Paraná 25.07% 29, 33% 43.94% 56.37% 52.20% Pernambuco 30.19% 35.46% 48.23% 58.97% 55.63% Piauí 26.02% 32.83% 45.66% 58, 07% 54.71% Rio de Janeiro 26.12% 31.02% 48.29% 57.02% 53.71% Rio Grande do Norte 29% 35.23% 45.46% 56.12% 53.54 % Rio Grande do Su l 25.58% 30.47% 46.56% 59.88% 55.05% Rondônia 23.98% 28.91% 41.31% 50.44% 46.41% Roraima 23.05% 28.56 % 38.45% 49.20% 45.70% Santa Catarina 26.76% 30.41% 53.21% 61.13% 54.28% São Paulo 24.83% 29.06% 43.33% 56 , 04% 52.56% Sergipe 28.88% 34.31% 46.24% 56.43% 51.91% Tocantins 21.74% 28.08% 41.22% 49.53% 44.88%

In all cases, the first week (March 3 to 9) recorded isolation rates between 20% and 30%. In the following week (10 to 16 March), the values ​​went up, and were between 27% and 40%.

A more consistent increase could be seen in the week of March 17-23, when quarantine became more strongly recommended. During this period, the states recorded isolation rates between 38% and 53%.

Scenes of agglomerations across Brazil put authorities on alert

The peak of social isolation, however, was reached in the week of March 24 to 30, when all states, with the exception of Roraima and Tocantins, had at least 50% of smartphones monitored without considerable movement.

In the last week analyzed, however, between March 31 and April 6, the 27 federation units showed a reduction in isolation rates.

In the most recent pronouncement on the national television network, last Wednesday (8), President Jair Bolsonaro again criticized the measures of social isolation, and considered that they are "the exclusive responsibility" of the governors.

Public Market in Florianópolis with queues in the last week - Photo: Marcelo Siqueira / NSC TVPublic Market in Florianópolis with queues in the last week - Photo: Marcelo Siqueira / NSC TV

Public Market in Florianópolis with queues in the last week – Photo: Marcelo Siqueira / NSC TV

Santa Catarina, which was among the 3 states that most managed to keep the population at home, was the one that registered the biggest percentage drop in the isolation index, going from more than 61% to less than 55%.

On the other hand, Amazonas, which is among the worst isolation rates in the last week of March, had the smallest variation, less than 1 percentage point.

In April, no Brazilian state recorded isolation greater than 60%. Goiás (58.44%) and Distrito Federal (57.98%) were the ones that came closest.

At the other end, Tocantins (44.88%), Roraima (45.7%), Rondônia (46.41%), Mato Grosso (46.98%), Mato Grosso do Sul (47.59%) and Acre ( 48.66%) are unable, according to the data, to keep half the population in their homes.

São Paulo, which also monitors isolation using data from cellular operator Vivo (see below) also recorded a drop in isolation. Last Thursday, the index was the lowest since the quarantine began.

In most situations, the capitals registered worse isolation rates than the states over the 5 weeks analyzed:

  • in 16, isolation was lower than the state average for most weeks;
  • in 3, isolation was higher than the state average for most weeks;
  • in 4, the isolation was similar, with a difference of, at most, 0.5 percentage point

In the other 4 capitals, there was variation. In some weeks, the index in the capital was better, in others, worse.

In Salvador, Vitória and Belém, for example, there was greater movement than in the rest of the respective states in the first two weeks. In the third, the isolation was similar. However, in the last two weeks analyzed, the residents of the capitals stayed more at home.

The trend was also repeated in Cuiabá, Belo Horizonte, Florianópolis and Palmas, but the "turning point" happened in different periods.

The importance of isolation

In an interview with G1, infectious disease physician Julio Croda, a professor at the Federal University of Mato Grosso do Sul (UFMS) and a researcher at the Oswaldo Cruz Foundation (Fiocruz), stated that he is developing a study that aims to estimate the lack of hospital beds and ICUs of according to the increase in the displacement of people. It uses data from In Loco.

“We are doing research trying to validate isolation rates to predict the number of cases in the future. As isolation is the best control measure in the number of cases, perhaps this isolation rate captured by cell phones is a good indicator for predicting cases in the future ”, he says.

“We want to know how much social isolation reduces the number of cases. Can we say that with 58% of isolation, the number of cases decreases? Or not, that with 58% of isolation, the cases continue to increase? ”, He adds.

Croda explains that currently mathematical models use data from confirmed cases to predict the increase in coronavirus transmissions. But, according to him, this method has problems. “How to design if you don't understand how many cases you have right now? Most mathematical models work with the number of confirmed cases, but this has the problem of underreporting, due to the lack of tests ”, he says.

He cites Manaus data as an example. The data shows that, on April 6, the capital of Amazonas had 50% of the people in isolation. On Wednesday (8), Manaus recorded 58% of isolation after the news of the increase in cases and a possible collapse of the health system.

“Certainly, this is due to all the reports that have passed (talking about Manaus) and to the minister's announcement (Luiz Henrique Mandetta) saying that Manaus is worrying. You see the impact in real time on people's lives ”, he concludes.

Google and phone operators also provide data

Google released on Friday (10) a new edition of its movement report. The study points to a reduction in isolation in 5 categories in Brazil: workplaces, parks, commerce, public transport and recreation.

In isolated actions, telephone operators are also collaborating with the authorities, providing location data for their customers. The actions, however, are punctual.

In São Paulo, Vivo is providing handset location data for 39 of the 645 municipalities to the State Government. The state government said the system is being updated daily to include information regarding municipalities with up to 30,000 inhabitants.

On Thursday (8), for example, the isolation rate in the monitored cities was 50%. According to the State Health Department, the ideal adherence to control the spread of Covid-19 is 70%. Thus, the number of beds in the health system must be sufficient to serve the population.

In the city of Rio de Janeiro, the city government's partnership is with Tim. The company is committed to sending the location data of its users in the city. Sought by G1, the operator gave no further details.

Google also released this type of survey. Only the last update was on March 29th. The company has not yet predicted when it will have more updated data.

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