CHEO researchers have launched a study to understand how and why some family members develop immunity to COVID-19 when exposed to someone in the same household who has tested positive for the disease.
“It happens more often than you would think,” said Dr. Maala Bhatt, an investigator at the CHEO Research Institute and director of emergency research. “We have seen that there are households where there are positive people and negative people despite a lack of social distancing.”
The study, she said, will explore what’s happening on a cellular level among people who test negative in a household with COVID-19: Is there evidence they’ve been exposed to the virus? Do they have the antibodies that signal they’ve developed an immune response to a COVID-19 infection? What kind of protection do those antibodies confer against the disease? And does that response differ by age or gender?
Bhatt is now recruiting families to take part in the year-long study. She’s hoping to enrol 75 children and 125 adults from families who have had a COVID-19 infection in their households during the pandemic.
All participants will have blood tests at four points during the year to test for antbiodies specific to SARS-CoV-2, the virus that causes COVID-19. They’ll all be informed of their test results, which means family members will know if they’ve developed an immune system response to the disease.
The study, Bhatt said, may also help scientists better understand how a COVID-19 infection spreads inside a household, how long an individual’s immunity lasts, and the roles that antibodies and T-cells play in conveying that immunity.
Antibodies are proteins that lock on to foreign invaders such as COVID-19 and mark them for elimination, while T-cells can kill those infected cells and regulate the body’s overall immune response.
“I think the study has enormous public health consequences,” said Dr. Bhatt, who’s also an emergency medicine physician at CHEO.
“We first need to understand whether the antbodies are actually protective against subsequent exposure. And if they are, then having a better understanding of how you become immune and who becomes immune would allow us to more reliably reopen, or keep open, recreational activities, schools, and other gatherings involving children and families.”
Children have proven mostly resilient to the effects of COVID-19 . According to the U.S. Centers for Disease Control and Prevention, most children who contract COVID-19 suffer mild symptoms or none at all, but they can spread the disease while asymptomatic.
Some researchers have theorized that children are less susceptible to the virus because they’re more often exposed to other, mild coronaviruses, such as those that cause the common cold, in schools and daycares. That exposure, they believe, may offer children a more robust immune response to SARS-CoV-2.
Bhatt said the CHEO study will explore that theory by testing participants for antibodies to four seasonal coronaviruses. Researchers will then be able to assess whether they offer children and their parents some kind of protection against COVID-19.
“The theory is, perhaps, that young children and the parents of young children are relatively protected compared with older people,” she said.
Studies have shown that, even in areas hard hit by COVID-19, most people do not have antibodies to SARS-CoV-2 in their bloodstreams. In New York, serological surveys found 23 per cent of people had those antibodies, compared with 18 per cent in London and 11 per cent in Madrid.
Those interested in enrolling or learing more about the study can email [email protected]
Copyright Postmedia Network Inc., 2020
