The drop in the moving average of Covid deaths in Brazil should be viewed with caution; see expert analysis | Coronavirus

• Week until September 5: average 819 deaths per day, a reduction of 17%
• Week until September 7: Average 784 deaths per day, a 17% reduction
• Week until September 8: Average 691 deaths per day, 26% reduction
• Week until September 9: Average 679 deaths per day, 25% reduction

The news is good, but according to experts heard by the G1, the data must be interpreted with caution, since the records are recent and already affirm that this is the trend of the pandemic in Brazil.

To explain the main points of the topic, the experts answer the following questions below:

1. Does the fall of the moving average represent the reality of the whole country?
2. What explains the drop in the moving average of deaths?
3. Does the decline mean that Brazil has reached the peak of the pandemic?
4. Does the fall mean that Brazil has achieved herd immunity?
5. Will the falling moving average of deaths be constant from now on?
6. Can we have a second increase in deaths as high as the one recorded at the peak?
7. Is it already possible to relax the isolation measures?

See the answers below:

1. Does the fall of the moving average represent the reality of the whole country?

Epidemiologist Paulo Lotufo affirms that it is necessary to carefully observe the national moving average, since Brazil has different epidemics happening at the same time.

“The coronavirus did not reach all of Brazil at the same time, it first reached the capital of São Paulo and spread. It is difficult to talk about the pandemic in Brazil as a whole, because it has its own reality in each place, it has very different dynamics”, says Lotufo.

Therefore, the epidemiologist prefers to analyze the epidemic curve for each state separately.

“Much of what we see in the national moving average is the result of the pandemic situation in São Paulo and Minas Gerais, the most populated states. The interior of São Paulo managed to control deaths in this period, for example, this is reflected in the national average. On the other hand, deaths continue to rise in some states, “he says.

In fact, when Brazil presented the second drop in deaths in the moving average, on September 7, 17 states – of the 26 states plus the Federal District – showed a de facto reduction (SC, ES, RJ, DF, GO, MT , AC, AP, RO, AL, BA, MA, PB, PE, PI, RN and SE), while two still had an increase in deaths (AM and RR), and the rest remained stable.

The infectious disease specialist Alberto Chebabo, from the Brazilian Society of Infectious Diseases, also points out that the last two moving averages went through a holiday followed by the weekend, which could have interfered with the registration of deaths.

“On Monday we had 315 deaths reported, which is a very low number compared to the previous days, which has already exceeded a thousand. This number probably had an impact on the holiday [7 de setembro]. Notifications generally drop during these periods, ”says Chebabo.

2. What explains the drop in death in the national moving average?

The epidemiologist Pedro Hallal, dean of the Federal University of Pelotas (UFPel), explains that, unlike the European countries that managed to contain the spread of the virus through strict public health policies, the fall in deaths in the moving average Brazilian is a result of what scientists call the “natural history of the disease.”

“We did little isolation policy, we failed with public health, we could not contain the virus, we let the ‘natural history of the disease’ follow, in which a virus naturally reduces its spread when it reaches its own limit. That is what it is. happening right now in Brazil ”, says the epidemiologist.

Hallal recalls that in April, the Ministry of Health predicted that the epidemiological curve would begin to decline in June or July, but since the measures to contain Covid-19 were not taken in time, the peak of the pandemic became a plateau. , killing more than a thousand people a week for weeks.

“The virus is showing us that its natural history was much longer than that. Our curve lasted from March to September due to the fact that Brazil systematically failed to comply with the recommendations of science, such as the blockade and the distance. We paid the price, we had the curves the longest epidemic in the world, “says Hallal.

3. Does the decline mean that Brazil has reached the peak of the pandemic?

According to the infectologist Chebabo, all of Brazil has already reached the peak of the pandemic. “We are in a phase of reduction in the number of cases precisely because we have reached the peak in all states. So the trend now is to decrease, but we have to wait to see if the decline continues,” says Chebabo.

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“[Em epidemias] You have a spike, and after that the transmission continues, but at a lower threshold. This is what is happening now in Brazil and what has happened in almost the entire world. It is the natural evolution of the disease ”, compares the infectologist.

4. Does the fall mean that Brazil has achieved herd immunity?

Herd immunity occurs when a large enough part of a population has been naturally infected and has developed a defense against the virus. As a result, the virus cannot spread.

“In a group immunity, you have a very low circulation of the virus because most people are immune. This did not happen in Brazil, the virus continues to spread from person to person here, it is in intense circulation,” says Chebabo.

A UFP study in July showed that, despite more than 120,000 deaths in the country, only 3.8% of Brazilians have already been infected with the coronavirus.

“This is nonsense, it is speculation, we still do not have a secure basis to talk about herd immunity in the pandemic. We do not know the virus well and we know little about how immunity works,” says Lotufo.

For Hallal, herd immunity is not a solution to contain the pandemic, since, to reach it, millions of Brazilians would still have to be infected.

“Herd immunity should not be the objective of a health policy in the pandemic, it is not responsible, it would cost many lives,” says the president of the UFPel.

5. Can we have a second increase in deaths?

There is the possibility of a second wave of cases and deaths worldwide, but, in the case of Brazil, an increase should not be as high as that recorded at the peak of the pandemic.

“We cannot predict that there will be a second wave and how big it will be, but the trend is that, if there is one in Brazil, it will be less than the first because we already had a very large percentage of the infected population,” he explains. Hallal.

In European countries, on the other hand, a second wave would tend to be greater than the first because the countries were able to protect the population with blocking and distance measures.

“European countries, due to the strict measures they have adopted, have a large part of the population that has not been exposed to the virus. It may seem like a disadvantage, but if a second wave comes, now we know the infection better and we will soon be able to have a vaccine, “he says. Hallal.

6. Will the drop in the moving average of deaths be constant from now on?

Not necessarily, as there are still many people susceptible to the virus.

“The drops are still recent. We need to monitor for once if the trend will continue. The virus has not stopped circulating,” says Chebabo.

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7. Is it possible to relax the isolation measures?

For Hallal, it is possible to loosen the confinement measures and think about reopening some activities, but with restrictions and analyzing them on a case-by-case basis.

“The fall of the moving average does not mean that it is possible to resume all activities. On the other hand, when the epidemiological curve is descending, it is possible to plan a gradual recovery of the economy and the epidemiological scenario of each state must be taken into account, I would even say that of each city, ”says Hallal.

Experts believe that this is not the time to promote crowds or reduce social distance. As an example of the resumption without crowding, Hallal says that it is already possible to hold team sports championships, but with all the measures against transmission (testing and isolation of those involved), and without an audience.

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“Now is the time to go back to football, for example, but it is not possible to resume championships in the pandemic with the presence of the public,” he exemplifies.

In this logic, face-to-face classes in schools and universities should be the last activities to resume. “The classroom is a place that does not allow much distance,” Hallal warns.

As recommended by the World Health Organization (WHO), the distance between people to avoid the transmission of the coronavirus by droplets expelled when talking, laughing or coughing should be 1 and a half meters to two meters, in addition to the use of the mask.