Largest study ever done in summer camps reveals little virus is spread by children

Children and adolescents who have participated in 22 summer camps in the Barcelona area have shown a much lower capacity to transmit the coronavirus, up to six times lower, than the general population around them.

This is the main result, still preliminary, of the largest study carried out to date on the dynamics of transmission of the virus in minors. The research has been carried out by a team from the Sant Joan de Déu children's hospital in the Catalan capital. The authors have chosen summer camps for being "assimilable environments or similar to those of schools."

• Education is still studying how to reconcile the quarantine of children and the work of their parents

The study has followed for five weeks "more than 1,900 people, including children and monitors from 22 summer schools in the Barcelona area, in an urban environment," explained the head of pediatrics at the hospital, Juanjo García. "Every week a group of hospital staff traveled to the camp and took saliva samples to perform a PCR," he added. This type of screening test has been one of the novelties of the study, since it is usually done with blood samples.

"During the five weeks that the investigation has lasted, we have been able to detect 39 new cases", of which 30 of them were in children, has continued Iolanda Jordan, the main researcher. “These children had 253 contacts that were boys and girls from their respective coexistence groups. Of these, only 12 infections occurred, which represents 4.7% and a reproduction rate R of 0.3. It is a low R, six times lower than the R that we found in the general population, which ranged between 1.7 and 2 ″, added Jordan in relation to the same neighborhoods where the summer camps took place.

Another outstanding finding, Jordan continued, is that "children under the age of 12 have the same ability to transmit as those between 13 and 17."

Clues for back to school

The authors have highlighted that they have encountered "a direct correlation between the incidence in the general population and the index cases that we found in summer schools" held in those same areas. "This leads us to think that the role of summer schools [in the transmission of the virus] has been really low," they have defended.

“These data give us clues regarding the opening of schools,” Jordan explained. "If we do things with a series of strategies, the importance of opening schools will probably be small [in the general incidence of the disease] and we will be able to open them safely and with the lowest possible transmission rates", has added.

The most important of these strategies are bubble groups (in which children do not mix with those in other classes or activities) and hand washing. In the first case, these closed groups not only "have helped to have these low transmission rates" but, once a case is detected, they have made it easier to follow the "traceability of contacts" and to decree "more selective quarantines".

“There were 12 infections, which is 4.7% and a reproduction rate R of 0.3. It is a low R, six times lower than the R that we found in the general population, which ranged between 1.7 and 2 ″

Regarding hand washing, Jordan has highlighted that “in the schools in which this hand washing was carried out more frequently, and specifically more than five times a day, infection rates were zero or lower, and therefore so this is a very important measure to be considered ”.

Manel del Castillo, manager of the Sant Joan de Déu Hospital, stressed that "it is probably the most important study at an international level that has mobilized more than 60 people during these months". He also wanted to underline "the effort made" to have these first results before the start of the school year in order to provide evidence of the challenge posed by the reopening of classrooms.

The results of this research, he added, have already been presented to the World Health Organization (WHO) and the European Center for Disease Control and Prevention (ECDC).

The study is part of the Kids Corona platform, which for months has been trying to shed light on the impact that the pandemic has on the child population and the role of this population group in the dynamics of virus transmission. "In June we already saw the results of the first home study, in which we saw that in families in which the father or mother had had covid, children are infected in similar proportions than adults," explained Del Castillo, although the infection occurs in these cases in a much milder way.

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