Understanding the transmission capacity of COVID-19 from children to other children or adults is a key question with substantial educational and social implications. To answer this question, the SJD Barcelona Children's Hospital has conducted one of the largest studies carried out worldwide to evaluate the infectiousness and transmission of the SARS-CoV-2 coronavirus among the child population in a school-like environment over a five-week period.
This is a research study carried out in 22 summer camps in the Barcelona area, systematically collecting samples from 1,905 participants. In addition, other cohabiting groups from other camps in which one of the children or monitors had been diagnosed with COVID-19 were also studied, reaching more than 2,000 study participants.
This study is part of the Kids Corona platform, which aims to answer these fundamental questions.
At the start of the pandemic, children were confined at home to protect them, as they were considered a vulnerable group. This meant that there were no data available on the transmissibility of the virus in children.
Owing to the imminent return to schools, addressing this question is paramount in order to provide valuable information on how to safely open in September. The studies that are included within the Kids Corona platform have been designed to answer these and other similar questions that have not yet been resolved and generate scientific and social debate.
To answer this question, we have designed various projects that start with children infected with COVID-19 and study those with whom they regularly have or have had contact. This will allow research into the manner in which children transmit the infection as well as into the extent they infect and become infected.
The most ambitious study to answer this question is that of summer camps, which has periodically and systematically looked at the proportion in which children have and transmit COVID-19. This initiative was funded by substantial private donations, required the deployment of a team of more than 60 professionals and was designed and monitored by several national and international experts, including the BIOCOMSC [Computational Biology and Complex Systems] of the Polytechnic University of Catalonia (UPC), the Barcelona Institute for Global Health (ISGlobal) and the Centre for Genomic Regulation. In addition, it was conducted in coordination with the Department of Health of the Government of Catalonia (Spain), following its line of action regarding COVID-19 and children.
This substantial project will be complemented by the case study of children with a positive PCR test result and their contacts, both those treated at the SJD Barcelona Children's Hospital and those who contact the hospital after receiving a positive PCR result.
The results of these studies will provide key information to understand to what extent children can become infected and spread COVID-19. These data will be essential to help decide the best strategies to continue the educational and social life of children, which will also have a direct impact on adults.
How is coronavirus transmitted in a school-like environment?
What have we discovered so far with our research? (updated August 26, 2020)
The research team of the Kids Corona platform has systematically analyzed samples of more than 2,000 participants in summer camps in the Barcelona area for five weeks.
The preliminary results of the PCR tests, in which we take a saliva or nasopharyngeal sample to detect the presence of the coronavirus, have identified a total of 39 index cases (new onset): 30 children and 9 monitors.
The 30 pediatric cases came into contact with 253 children during the camps (belonging to their bubble groups), 12 of which (4.7%) were infected (secondary positives), which represents a local empirical reproduction number (R) of 0.3. This rate is almost six times lower than that of the general population at the time of the study (1.7 to 2) in the areas where the camps were held.
Most of the pediatric index cases (22) detected did not transmit any infection in the camps. Five index cases transmitted the infection to one contact, two to two contacts and one to three contacts. Regarding the ages of the children analyzed, it should be stressed that, in this study, the younger children (under 12 years of age) were found to have the same propensity to transmit the disease as the older children (13 to 17 years).
The activities took place in a school-like environment, implementing basic risk containment measures: frequent hand washing, small bubble groups, use of a mask and primarily outdoor activities.
The study shows that the distribution of children in bubble groups is effective in containing the transmission of the infection, in facilitating the traceability of contacts and in allowing selective quarantine. In addition, protocolized hand washing five or more times a day has been associated with a decrease in the transmission of the disease.
A high correlation has also been found between the incidence of infection in the general population and the number of index cases detected in camps from the same area, which suggests that participants in summer camps have not been substantial transmitters of the disease and that proactive screening in high incidence areas can be very effective.
Although some limitations of the study must be taken into account, such as the reduced time of the study (five weeks) or the fact that many of the activities of the summer camps have been carried out outdoors and with small groups, meaning that the results cannot be directly extrapolated to other conditions, the data obtained gives hints to open schools in September in a safe and controlled way, applying measures such as those that have been implemented in summer camps: bubble groups, use of masks and frequent hand washing.