Is back to school safe in the pandemic? What research from foreign universities say

 The end of July or the beginning of August usually marks the period of back to school in Brazil. In 2020, however, the COVID-19 pandemic posed a big question mark at that time. Is it safe to resume face-to-face classes in Brazil? There are several researches on the subject, and none of them is able to give a conclusive answer.

To address this issue, we will now discuss research done at some of the best universities in the world . The question is important because, according to a UNESCO estimate , but over 60% of school-age children in the world had some change in their pace of study during the pandemic.

On the other hand, these children have great potential for spreading the disease, according to Science Magazine. If on the one hand it is true that they have less chance of becoming infected, on the other hand it is also true that they have more opportunities to become infected. That's because they circulate between different groups, touch more people and bring their hands to their faces more often. They also have more difficulty wearing masks and less self-discipline to keep them on their faces.

Therefore, understanding the best way to go back to face-to-face classes is essential to save lives. In Sweden , for example, where classes were not even interrupted, few children died of the disease, but many teachers ended up infected and died from contracting it from asymptomatic students.

Is back to school safe during the pandemic?

What a Harvard University study says

Researchers at Harvard University on August 19 published an article in the Journal of Pediatrics about the role that children can play in the transmission of COVID-19. The study addressed 192 children and adolescents going to the hospital or being treated for COVID-19 or multisystemic inflammatory syndrome. The researchers took blood samples, as well as oral and nasal mucus, from the participants.

Of the 192 children, 49 were infected with SARS-CoV-2 (the virus that causes COVID-19). None of them had comorbidities, which in adults can increase the risk of infection. And among them, 25 had a fever: the other 24 either had no symptoms, or had non-specific symptoms - that is, symptoms that did not immediately indicate that they were infected with the new coronavirus.

In addition, the viral load found in the nasal mucosa of children was "significantly higher [than the viral load found] in adults hospitalized with severe cases of the disease". In other words: even without showing symptoms, they had the virus in their bodies, and in great volume.


"We found that children can carry high volumes of the virus in their upper airways, particularly early during a SARS-CoV-2 infection, and still show relatively moderate symptoms, or even show them," says the study. The data therefore show that children can carry high viral loads, "which is an essential consideration when reopening schools and daycare centers" according to the scientists.

For the purpose of preventing the spread of the disease, therefore, the researchers consider that "it is critical to identify infected children as soon as possible for quarantine reasons". But they recognize that "children show few, if any, symptoms" and that "when present, they can also refer to symptoms of illnesses unrelated to COVID".

Therefore, if schools choose to reopen, the researchers consider that “it would be ineffective to have symptoms or temperature monitoring to identify” infected children. "Instead, infection control measures should try to minimize the possibility of viral spread, focusing on strategies such as social isolation, wearing masks or remote learning," says the study.

Without these measures, according to Harvard scientists, "there is a significant risk that the pandemic will persist, and children could take the virus to their homes, exposing adults who are more likely to develop severe cases of the disease." Therefore, the study concludes that "if schools reopen without the necessary precautions, it is likely that children will have a greater role in this pandemic".

Another study: University College London, University of Sydney, University of Copenhagen and more

A slightly less recent survey, published on August 3 in The Lancet , used a different method to answer the question. In it, researchers from the Department of Applied Health Research at University College London , the School of Physics at the University of Sydney and the Department of Mathematical Sciences at the University of Copenhagen, among others, used mathematical modeling to simulate a reopening of schools.

Essentially, the idea is to create a simulation of what would happen in several cases of schools reopening. For this, they use data on chances of infection obtained in other research to create a model that is as close as possible to reality. It is, of course, still a mathematical modeling, but as accurate as possible.

The researchers modeled six possible scenarios. These scenarios are the combination of two possible school reopening strategies (full-time, or on a rotating basis, with half the students going to class each week, alternately) with three testing scenarios (without additional testing and 68% tracking) contacts, with additional testing and 68% contact tracking, and with additional testing and 40% contact tracking).


After the simulations, the researchers concluded that it would be possible to prevent an increase in cases of COVID-19 caused by the return to face-to-face classes. For that, according to their modeling, two conditions would be necessary.

First, that 59% to 87% of people with symptoms were tested at some point during the infection (the percentage varies according to the simulated scenarios). Second, that there should be enough contact tracking so that, if someone were to test positive, that person and all those with whom he or she recently had contact would be isolated and quarantined.

“However, without these levels of testing and contact tracking, reopening schools and gradually relaxing isolation measures is likely to induce a second wave [of the pandemic] that will peak in December 2020, if schools reopen full-time in September, or February 2021, if the rotating system were adopted, ”concludes the study.

According to the researchers, in the event that this "second wave" happens, it could be 2.0 to 2.3 times greater than the first wave of the pandemic. But what if children and young adults were only 50% more likely to become infected than adults? The researchers also simulated these cases, and say that even in it, "we still saw that a comprehensive and effective strategy for testing, tracking contacts and isolating would be necessary to avoid a second wave of COVID-19".

Therefore, if mathematical modeling is adequate, schools must be prepared to carry out huge amounts of tests, and have a way of tracking the people each child comes into contact with. Without this, the reopening of schools could lead to an even greater wave of infections.

Brazilian simulation: what UFABC, Unifesp, Ufscar and the University of Bristol say

One objection that could be raised against the previous study is that it uses data referring to the United Kingdom. But two Brazilian study groups did a similar simulation with Brazilian data. They are the Ação Covid-19 and Repu groups , which have researchers from UFABC, Unifesp, Ufscar, IFSP, Bristol University (in England) and the Colombian Army Aviation School.

The groups used a public simulation tool that takes into account the size of the school, the level of respect for measures of social distance, and the level of respect for hygiene and safety protocols.

Following the protocol of the São Paulo State Department of Education, which foresees the return of 35% of students from public schools as of October 7, the researchers simulated what could happen in two schools in São Paulo. They also considered that there is a 39% chance that an infected person will transmit the virus to another, and that each school would be visited by an infected person every ten days.


With these data, they simulated what would happen to a public school with 400 students in 9,000 square meters. According to what the researchers told Folha de São Paulo, Even with the utmost respect for social isolation measures and hygiene and safety protocols, more than 10% of teachers and students would have been infected two months after returning to face-to-face classes.

Another simulation used data from a public school with 700 students and 6,500 square meters. Also considering the maximum respect for preventive measures, 46.3% of the school's teachers and students would have been infected two months after the return of the face-to-face classes.

Also according to the researchers, to control the spread of the disease, it would be necessary to reduce the percentage of public school students who would return to school to 7%. This is because of the physical characteristics of schools, which cause crowds of people.

It is also worth taking into account that the simulation only takes into account the time that students spend inside schools. She does not consider the time that children would spend on public transport, or their contact with relatives. According to the researchers, this simulation was “conservative”, and the dissemination could be much greater in denser schools.

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