B.C. immunity study to investigate mysteries of COVID-19 in children

Canada’s immunity task force is turning its attention to the country’s youngest population groups in an effort to better understand the extent to which children, adolescents and young adults contribute to the spread of COVID-19, and to obtain a more detailed profile of how the disease varies across the age spectrum.

On Tuesday, the federal-appointed task force announced it was supporting a new study led by the BC Children’s Hospital that will test thousands of individuals between newborn and 24 years old to determine how many have already had the coronavirus, even if unaware of it. Three other studies of children that are already up and running across the country will also receive support from the task force.

The studies resemble others across Canada that screen large numbers of individuals for antibodies that are formed by the body’s immune system in response to the coronavirus. The difference is that, up till now, most of those studies have not included children. The result will offer another clue to how COVID-19 is moving through the population and could inform strategies for vaccine deployment next year.

“We really have to understand children in terms of their susceptibility to infection, but also their role in transmission of infection in households,” said Tim Evans, who leads McGill University’s School of Population and Global Health and is executive director of the task force.

The British Columbia project, dubbed the SPRING study, is aiming to build up a sweeping portrait of the coronavirus pandemic among young people in the province and track its movement through time. Parents who wish to enrol their children in the study will be asked to fill out an online questionnaire and provide blood spots on paper using a finger prick test kit. Such tests do not reveal active cases of coronavirus but instead are used to reveal who has already had COVID-19 since the pandemic began.

The study is aimed at addressing some of the lingering mysteries around the coronavirus in children, including whether children are less likely to become infected or whether their infection rates are similar to adults but with fewer symptoms. Other studies have provided conflicting evidence around this question, which has made it hard to predict what kind of transmission rates to expect in schools and other settings where children are interacting with each other and with adults.

Study leader Manish Sadarangani, who is director of the hospital’s vaccine evaluation centre, said that comparatively low case numbers of COVID-19 among children do not mean that children will not be an important consideration during a vaccine rollout.

“When the first wave of vaccines are available… clearly kids are not going to be a high priority for vaccination,” he said. “But I think moving further down the line we know, from influenza, that vaccinating children is really important because it breaks transmission to the elderly.”

Dr. Sadarangani added that when he and his colleagues began planning the study they initially intended to look only at children, but they expanded their focus to include young adults in order to capture how much COVID-19 has penetrated into an age group that was one of the first to see a rise in case counts starting in late summer.

“We’re planning to recruit equally at different ages,” from preschool to university age, Dr. Sadarangani said. The study will also sample from across the regions of the province and include a diverse and representative range of participants.

If the study manages to recruit widely enough, the results could improve computer models that try to predict the future trajectory of the pandemic, particularly in settings where children make up a significant share of the population. The key is to have a better handle on transmission rates among children.

“If we can compare that to adults then we’ll have some information about how COVID is spreading in schools,” said Caroline Colijn, a mathematician and disease modeller at Simon Fraser University in Burnaby, B.C., who is not involved with the Children’s Hospital study.

The SPRING study ultimately aims to include 16,000 participants, but Dr. Sadarangani the immediate goal is to recruit the first 2,500, divided evenly between five sub-groups according to age, and to follow those groups through time as the pandemic ebbs and flows. So far 300 have signed on since recruiting began two weeks ago.

The study has received $1.3-million in support from the Immunity Task Force. Funding has also been allocated to studies tracking COVID-19 in children and teens in Montreal (EnCORE study) and two cohort studies led by researchers at McMaster University in Hamilton (CHILD study) and Toronto SickKids Hospital (TARGet Kids.)

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