Quirks & Quarks

How aging increases vulnerability to COVID-19 and how pollution can make it worse

Your body's ability to fight off viruses naturally declines as you get older, becoming more weak and less targeted, and pollution exposure makes it even worse.

The immune response gets weaker and less targeted as we age

Health care workers speak with patients at a drive-thru COVID-19 assessment centre in London, Ontario, on March 17, 2020. (Geoff Robins / AFP via Getty Images)
Listen23:08

As COVID-19 case numbers continue their frightening rise in countries around the world, it's clear not everyone reacts to the virus the same way. 

On the one end of the spectrum are otherwise healthy children and younger people, who for the most part, only seem to get mild to moderate symptoms, if they get symptoms at all.

But the older you are, the more vulnerable you are to the serious consequences of a COVID-19 infection. Futhermore, conditions like cardiovascular, metabolic or respiratory diseases, or a compromised immune immune system, can all make the disease outcome even worse.  

According to Alyson Kelvin, a virologist from Dalhousie University, as we get older our immune system becomes less able to fight off the virus. For example it produces fewer antibodies which are proteins that can attack viruses. Inflammation also tends to increase as the body can produce an increasingly uncontrolled immune response, including a dangerous excess of of immune molecules called cytokines.

"These inflammatory cytokines, specifically one called IL-6, has been shown to be significantly increased in patients who have poor outcomes [of COVID-19]," she told Quirks & Quarks' Bob McDonald.

Your body's immune system naturally declines as you age, making it harder to fight off pathogens like the COVID-19 coronavirus. (Andrej Isakovic / AFP via Getty Images)

Pollution can also significantly affect our immune systems

Chemicals we're exposed to every day, from air pollution, to contaminants in food and drink, to toxic substances we willingly expose ourselves to — through activities like smoking — can all affect our immune system, and increase our vulnerability to serious infections like COVID-19.

Dr. Chris Carlsten, the head of the University of British Columbia's Division of Respiratory Medicine, told Bob McDonald the effect of environmental exposures on our immune system is "very strong and much stronger than we thought." 

"In 2003, the evidence showed that those that were exposed to elevated air pollution had nearly doubled the risk of death from that SARS virus."

He added that preliminary data on COVID-19 suggests the risk of infected smokers "progressing into a more serious form of the disease - a more dangerous situation - is at least ten times [greater] in smokers."

That antibody production system is thrown off dramatically in the face of pollution ... becomes problematic because the antibody system is not working as it should.- Dr. Chris Carlsten, UBC

Inhaled pollutants and toxins can affect the epithelial cells that cover the surface of the lung. This can reduce our ability to clear particulate matter — like viruses — so that they have more opportunity to invade lung tissue. Pollutants also can affect the immune response once the virus gets inside the cells.

"That antibody production system is thrown off dramatically in the face of pollution -- and then the co-exposure to whether it's a virus or an allergen or a bacteria -- becomes problematic because the antibody system is not working as it should," he said. 

Carlston added it's not just pollution we breathe that can affect our immune system, but also toxins we can ingest like phthalates, which are present in plastic.

"Phthalates, just as an example of something other than air pollution, have been shown to also affect the immune system and its ability to respond to common insults." 

Produced and written by Sonya Buyting

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