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SJD Barcelona Children's Hospital investigates why children are more protected against COVID-19

The Hospital launches the campaign #ElsInfantsSónClau (Children are Key) to recruit 500 families with children in which at least one adult has tested positive for the study.

Lab technician working during coronavirus outbreak at SJD Barcelona Children's Hospital
One of the researchers in the SJD Barcelona Children's Hospital research laboratory.

The coronavirus SARS-CoV-2, which is causing thousands of deaths worldwide is, surprisingly, showing a particularly low incidence among children, even though children are typically one of the groups most at risk of suffering severe respiratory disorders.

In China, where the epidemic began, only 2% of people who became ill with COVID-19 were under the age of 19. In Catalonia and the rest of Spain, the incidence is even lower, at 1%. Of the 24,707 cases recorded in Catalonia up to Tuesday 7 April, only 242 are children and young people from 0 to 19 years of age. Not only do children suffer less respiratory distress syndrome from coronavirus SARS-CoV-2, but also when they do, they have milder symptoms. In Spain, only 0.6% of affected children have been hospitalised so far and there have thankfully been no deaths.

The figures are also low at SJD Barcelona Children's Hospital, which is providing a significant part of the care in Catalonia for pediatric patients and pregnant women and is taking referrals from 25 other hospitals so that they can focus their efforts on care for adults. Since 7 March, 407 PCR tests have been carried out at our hospital on children with suspected coronavirus and only 18 have been positive. Sixteen of these children had to be hospitalised, ​​but all have made or are making a good recovery.

Research platform

In this context, SJD Barcelona Children's Hospital has launched the Kids Corona platform with the aim of promoting research studies that help work out why children are more protected against this virus than the rest of the population. The ultimate goal is to identify the protective factors and find a treatment to extend the natural protection children have against COVID-19 to the adult population. Researchers believe that children are the key to overcoming the pandemic.

The role of the child population in the transmission of the disease is not yet understood. The aim of the research studies to be carried out at SJD Barcelona Children's Hospital is to clarify this aspect and to answer questions currently of concern to society, such as whether or not children transmit coronavirus to the rest of the population.The platform will also address infection in pregnant women, to investigate how it happens and what factors encourage it or slow it down.

Areas of research

Several studies will be carried out to find out why it seems that children are not infected, why some children who become ill have mild symptoms and others more severe, and how COVID-19 affects pregnant women and fetuses.

Kids Corona will work on four lines of research:

Microbiological research line. Researchers have found that most children who have had to be treated in hospital for COVID-19 are either newborns or over 6 years old. The disease is almost non-existent in children from 1 to 5 years of age. This suggests that the protection among children against the coronavirus may be related to nasopharyngeal microbiota, i.e. the microorganisms living in the nasopharynx and, specifically, certain species of bacteria. Children have very rich microbiota diverse in bacterial species which is lost with age.

The researchers aim to conduct a study to analyse the microbiota of children and compare it with adults, in the search for some element present in children but not in adults which may provide protection against the virus. They will also analyse the microbiota of children treated for COVID-19 to compare it with that of children treated for other respiratory infections.

Clinical research line. Children suffer a milder form of the disease caused by the new coronavirus than adults. Even in children with theoretical risk factors such as immunosuppression or chronic diseases, COVID-19 often does not become particularly severe. The true extent of infection in pediatric patients is not fully known because diagnostic tests have only been performed on patients meeting certain admission criteria and as yet there are no population studies for the region.

The researchers in this line aim to study the clinical and microbiological evolution of COVID-19 in diagnosed children and compare the clinical characteristics between patients who require hospitalisation due to its severity and those who can be treated as outpatients. The study of all these variables will help us characterise the behaviour of COVID-19 in the pediatric age group more precisely and may provide clues as to the most appropriate action to take once the social distancing measures can be relaxed, without jeopardising the more vulnerable sectors of the population.

Inflammatory response research line. This line will consider whether or not certain biomarkers may enhance the body's protection against the coronavirus. They plan to study an enzyme called angiotensin-converting enzyme-2 or ACE2, a receptor directly involved in how the virus enters cells to replicate itself. Researchers believe that in children the soluble part of this enzyme could be higher and hinder the entry of the virus. This is a pathway which has been studied before in other diseases caused by coronaviruses, such as SARS and MERS, and, if confirmed, could have direct therapeutic implications because it would make it possible to design drugs to combat COVID-19.

Researchers also plan to analyse whether or not children's immune response to the virus is different from that of adults. COVID-19 generates a very significant local and systematic inflammatory response affecting all organs, but primarily the lungs. In collaboration with Hospital Clínic, researchers from SJD Barcelona Children's Hospital are going to study the initial immune response to the virus and the subsequent evolution or degree of inflammation in children and adults.

Maternal/fetal line of research: Researchers in this line - which will be performed within the framework of BCNatal (Fetal Medicine Research Center) in conjunction with Hospital Clínic and will include cases from Hospital de Sant Pau - will analyse what factors determine the risk of COVID-19 in pregnant women and, if they have the infection, whether they remain asymptomatic. Various factors will be studied and data will be provided to pediatric groups to enable them to perform follow-up on their children. One of the main methods of research will be study of the microbiota, which the maternal/fetal research group studies in many other conditions and which may play an important role in protecting pregnant women against COVID-19 and in transmission to their babies. They will also use existing research platforms to correlate patterns of nutrition, the microbiota and the pattern of infection in pregnant women.

This knowledge will importantly provide much needed information for pregnant women, considering the large void in our understanding of how vulnerable they are to the disease. We also hope it will provide clues to understanding how children become infected, which may be highly relevant for further research to be carried out in children.

Hospital Sant Joan de Déu
SJD Barcelona Children's Hospital investigates why children are more protected against COVID-19