COVID-19 transmission rate drops, but cases still rise, says study

COVID-19 transmission rate drops, but cases still rise, says study

In the fight against the new coronavirus (SARS-CoV-2), an international Reviews classifies the growth of COVID-19 in Brazil as "stable or growing slowly". That's because the rate of transmission of the disease, known as the R rate, reached 1.01 on Sunday (9), according to a study by the university Imperial College, UK.

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In the country, the R rate decreased in relation to the previous week (it was 1.08) and is following this downward movement, which still does not indicate the retraction of COVID-19. After all, a rate of 1.01 means that every 100 people infected with the new coronavirus transmit the disease to another 101 people, that is, the number of patients still grows. The epidemic only declines when the number is less than one.

Transmission rate of the new coronavirus is in a downward movement (Image: Reproduction / Pixabay)

In the world, the highest R rates were estimated for Palestine, with 1.69, and for Puerto Rico and Japan, both with 1.55. The lowest rates are in Spain (0.42), Sweden (0.51) and Egypt (0.51). In South America, most countries are in this same group as Brazil, with the exception of Ecuador, where there is a decline (0.82), and Argentina, where the rate is growing (1.22).

The British study also predicts that Brazil should register around 7,400 deaths due to COVID-19 in the seven days following the survey, released over the weekend. This number is the highest among the 69 countries surveyed – however, the list does not include the United States, the largest epicenter of the coronavirus in the world.

Covid-19 in Brazil

The drop in the R rate nationally is also accompanied by the Oswaldo Cruz Foundation (Fiocruz). However, these numbers should be seen in a more regionalized way for the development of public policies. "Brazil is a very heterogeneous country", explains Juliane Oliveira, postdoctoral fellow at the Center for Data Integration and Knowledge for Health (Cidacs / Fiocruz).

"The ideal is to look at the smallest possible region, due to the question of heterogeneities. Looking at the state level is much better than looking at the country as a whole", defends the researcher. This is because there are still states with transmission rates above this level. In Rio Grande do Sul, Mato Grosso do Sul and Tocantins, for example, the rate is 1.2 – every 100 cases generating 120 new infections. In Amazonas and Pará, the rate is 0.9, indicating a drop in the rhythm of the pandemic, with 100 cases generating 90 new cases.

With this Reviews, the researcher at Fiocruz comments that the drop in the transmission rate demonstrates that the measures of social isolation had an effect on the control of COVID-19. In this sense, in São Paulo, the rate dropped from 2.1 on April 5 to 0.8 on April 8. After a further rise, the transmission reached 1.3 on April 14, a level that was maintained until the beginning of June. Last week, São Paulo had a transmission rate of 1.1, according to the CoVida Network panel.

According to the data collected, Oliveira recalls that the isolation measures arrived before the explosion of cases in some states, such as in the South Region and in Minas Gerais, which caused the pandemic to grow more slowly than in the first affected states. , such as São Paulo, Rio de Janeiro and Amazonas.

"The issue of tracking cases was missing. There is no point in taking distance measures without tracking and isolating cases. When you track and isolate, you cut the transmission," recalls the researcher about a measure that could help reduce the number of cases. current cases of COVID-19, as the virus would spread less. "When they opened, it started to rise again, because the cases were not yet under control", he adds about the lack of control among those who were sick.

To access the worldwide estimates of transmission rates for COVID-19, developed by Imperial College, click here. Now, to monitor the regional transmission of the disease in Brazil, access the Fiocruz platform here.