The novel coronavirus is primarily spread amongst adults who are about the same age. Within families, the virus is mainly transmitted from adults to children. Children are sometimes infected with the virus, but less often than adults. There were no families in which a child under 12 years old was the first patient in the family. These findings are from the first part of the ‘First Few Hundred’ study conducted by RIVM National Institute for Public Health and the Environment .
The results of the study on COVID-19 in Dutch families confirm the impression that children do not play a significant role in the transmission of the virus. They may become ill, but their symptoms are often very mild. This is a marked difference from the seasonal flu (influenza), where we often see children passing the virus to each other or to adults. This appears to occur far less frequently for the novel coronavirus. The findings from the study are in line with the results of research being done in other countries, including studies in China and South Korea. Following peer review, RIVM published the results in the Nederlands Tijdschrift voor Geneeskunde (NTVG), the leading medical journal in the Netherlands.
First part of the study: 54 families
For the purposes of the study, RIVM collected data on 54 families in the Netherlands that were contacted via the municipal public health service in Utrecht (GGD Utrecht) to take part in the study. The first family was visited on 23 March. Many of the participating households were the families of healthcare workers who had tested positive.
These 54 families comprised a total of 239 participants, of which 109 were children.
Data and samples
As each family joined the study, a nurse visited their household as soon as possible. The nurse then collected nose, throat, saliva and blood samples. The family also filled out a questionnaire about symptoms, the types of contact that each person had with the infected family member, the living situation, and any underlying health conditions. The family then kept track of their symptoms for a month and took stool samples. If a family member became ill, the GGD took nose and throat samples again to check if this person also had COVID-19. Samples were taken from the whole family 2-3 weeks and 4-6 weeks after the first home visit.
In order to monitor the role that children play in spreading the novel coronavirus, now that schools have reopened, RIVM will be adding 50 new families to the study. Families of children who have tested positive will be contacted via the GGD regarding participation in the study.
As a result of the ongoing studies in the Netherlands and in other countries, RIVM will be keeping track of the role played by children, childcare facilities and schools in the spread of the virus.