Is COVID harming immune systems? Here’s what we know, and what we don’t

A surge of viral illness across Canada, especially among children, has sparked questions about whether COVID-19 is to blame, but experts say there is not enough data to prove this.

A surge of viral illness across Canada, especially among children, has sparked questions among some infectious diseases experts about whether COVID-19 is damaging the immune systems of its patients and making them more susceptible to other illnesses.

But while there might be some evidence that COVID-19 is having an effect on some patients’ immune cells, it turns out there is still not enough data to definitively say SARS-CoV-2 is damaging every infected person’s immune system. There is even less evidence available to say COVID-19 is responsible for the current wave of respiratory illnesses that are swamping hospitals and ERs across Canada, according to some experts.

The question of whether the novel coronavirus is weakening immunity has been raised in a number of public forums in recent months as a theory that could explain not only why so many Canadians – notably young children – are contracting influenza, respiratory syncytial virus (RSV) and other viral illnesses across Canada, but also why many children are experiencing more severe illness than normal for these viruses.

Children’s hospitals across the country have been reporting record high numbers of patients in their emergency, intensive care and hospital units. The issue is so pronounced in parts of Ontario that a number of major children’s hospitals in the province have had to cancel non-urgent surgeries in order to redeploy staff to ERs and ICUs that are operating beyond capacity.

The situation is similar across the country, with children’s hospitals in Nova Scotia, Quebec, Manitoba, Saskatchewan, Alberta and British Columbia all reporting surges in patients – a situation that is adding significant strain to provincial health systems that were already cracking under the pressures of health worker shortages before the viral outbreaks.

Colin Furness, an infection control epidemiologist and assistant professor in the faculty of information at the University of Toronto, told Global News last week he believes COVID-19 may be partly to blame for the sudden surge of severely ill children, due to emerging evidence from some preliminary studies showing that COVID-19 harms the immune system.

“We know that COVID blocks the production of interferon, which is a red flag that cells wave when they’re being attacked. We know that there are other kinds of immune system impairment with COVID, and it’s going to take a little while to really try and explain that more clearly,” he said. “But it seems to be what’s going on, and it certainly fits the facts.”

Furness did stress, however, that it isn’t yet clear how much damage COVID-19 may be doing and what long-term effects this could have.