A look at the science behind COVID-19 reinfection, including what to expect and
who's most at risk.
By this point in the pandemic, you've likely had COVID-19 at least once. Maybe
twice. Perhaps even three times, as
some unfortunate Canadians have experienced, all while this virus
evolved to become increasingly savvy at infecting us.
It's clear that reinfections from this coronavirus are the norm, much like with
those behind the common cold. Unfortunately, that also means early speculation
about one-and-done bouts of COVID-19 offering immunity against future infections
has long gone out the window.
What's more hazy is just how often you can get infected with SARS-CoV-2 and
whether future infections will always be milder than the first, as the virus
finds a way into our bodies over and over again.
Reassuringly, scientists say that for most healthy adults including those with
extra protection from vaccination COVID-19 infections should get easier to
deal with as your immune system gains repeat training on how to handle this
particular pathogen.
"Your first infection with COVID is probably not invariably but probably
going to be the worst," said infectious diseases specialist Dr. Allison McGeer,
a professor at the University of Toronto's Dalla Lana School of Public Health.
"And then as you get more and more exposed to it, you get better and better
protections."
A transmission electron micrograph of SARS-CoV-2, isolated from a patient.
Scientists say the virus is capable of reinfecting humans again and again.
But just how often can it happen, and will it feel milder each
time? (National Institute of Allergy and Infectious Diseases)
Coronaviruses strike repeatedly
After months or even years of avoiding the virus entirely, it might come as a
surprise that COVID-19 can hit you more than once.
Early in the pandemic, some scientists spouted hopes around herd immunity that
if enough people caught COVID-19 or were vaccinated against it, collective
immunity against infection would reach a threshold where the virus wouldn't be
able to find new human hosts.
Unfortunately, that's not easy with a coronavirus.
First identified in humans in the 1960s, viruses in this family have likely been
striking us repeatedly for centuries. SARS-CoV-2 is just the newest kid on the
block.
"Four of those other family members cause about 30 per cent of our common colds,
and they reinfect us routinely," said Dr. Amesh Adalja, a senior scholar at the
Johns Hopkins Center for Health Security in Baltimore.
"We've all had multiple bouts of other coronavirus infections, and that's where
this virus was always headed. So reinfections are not something to be surprised
about."
They were rare, though, throughout the early part of the pandemic. SARS-CoV-2 is
hitting people again and again at this point, two-and-a-half years in, partly
because we're giving it the chance.
"This would have been happening much more frequently had we not all been staying
at home and keeping our distance," McGeer said. "It's not that the virus is
doing anything different than the virus would have done before; it's that we're
behaving differently."
Scientists say reinfections were rare throughout the early years of the
pandemic in part because people were largely staying home, whereas more
socializing is now giving the virus a chance to spread. (Marc-Andrι
Turgeon/CBC/Radio-Canada)
Layer in ever-more-contagious variants that are capable of dodging the
front-line soldiers of our immune systems, and you've got a recipe for
reinfections on a more regular basis. What's unclear is just how often this
virus will strike.
Four long-studied seasonal human coronaviruses seem capable of reinfecting
people every 12 months, according
to research published in Nature Medicine that involved scientists
tracking a group of healthy adults for more than 35 years.
But unlike that seasonal pattern, SARS-CoV-2 remains erratic more of a
constant roller-coaster than one big surge and drop in any given year.
In Canada and multiple other countries, a seventh wave is now underway,
fuelled by yet another immune-evasive Omicron subvariant, BA.5. It's
happening in the summer months well before the typical cold and flu season
and not long after earlier waves driven by other members of the Omicron
family tree.
McGeer, like many close COVID watchers, still isn't sure what path this
virus will take in the long term.
"Are we probably going to settle into winter activity? Yes, eventually, but
maybe not for another year or two," she said. "Is it for sure that we're
going to? Nope."
Epidemiologist Dr. Christopher Labos blamed COVID-19 reinfection risk on the
virus mutating. He also said there was no evidence of future variants
becoming increasingly milder.
Reinfections usually not worse than the first
What several experts who spoke to CBC News are more certain about is that
subsequent COVID-19 infections should feel milder than the first. That doesn't
mean a walk in the park, necessarily, but at least not as rough as your body's
first encounter with this virus.
"From all the literature I've seen, when reinfections do happen with increasing
frequency, they're not usually worse," said Angela Rasmussen, a virologist with
the University of Saskatchewan's Vaccine and Infectious Disease Organization in
Saskatoon. "And that's exactly what you'd expect, because that's how the immune
system works."
There are a couple of ways to train your immune system to fight off this virus
faster and smarter. One is being exposed to SARS-CoV-2 directly, which comes
with all the potential health consequences of an infection.
The other is getting vaccinated, allowing your body to learn about this
particular pathogen without facing those risks. (Consider that option like a
martial arts lesson, rather than scrapping it out in a surprise fist fight.)
Erin Wilson, a fitness teacher and actor in Halifax, has caught COVID-19
twice the first time last December and again in July. Both times the
virus hit her hard, leading to fatigue, coughing and chest congestion,
but she says the second time around felt a little easier. (Mark Crosby/CBC)
If you're vaccinated and catch COVID-19, the virus might still get by your
immune system's first line of defence your neutralizing antibodies and
sneak into your cells, Rasmussen said.
"Immediately your memory T-cells from your vaccination are going to say,
'Whoa, I've seen that guy before; time to go out and start killing these
cells that are infected with it,'" she explained.
In other words, a well-trained immune system can't prevent infection, but it
can often rapidly control it. That means an invader that might have once
wreaked havoc simply doesn't get that chance.
So far, that's been the experience for Erin Wilson, a fitness teacher and
actor in Halifax, who recently caught COVID-19 again after first getting
infected last December. (She's also vaccinated.)
The first round left her exhausted and in bed for days, "completely
incapacitated." Her next bout wasn't pleasant and several days in, she was
still battling chest congestion, a cough, and fatigue but she did notice
it was a little easier.
"The second time around did not knock me out as much," Wilson said.
Not every reinfection will be 'benign'
So, if you've already gotten through COVID-19 at least once before, should
you throw caution to the wind and catch it again and again? Not exactly.
The virus doesn't treat everyone equally, stressed Adalja, from Johns
Hopkins. "What we're learning is that not every second infection or third
infection is going to be benign and that's particularly going to be true
when you're dealing with higher-risk populations."
One study focusing on U.S. veterans who are mostly older men
found reinfections in that group appeared to come with a higher risk of
death or hospitalization.
The paper, which hasn't yet been peer-reviewed, made headlines in recent
weeks. But several experts, including Adalja, cautioned against reading too
much into its early findings, which may not apply to the general population.
However, while repeat infections should feel milder for most healthy
individuals, he said it's important to keep in mind your shifting risk
factors for severe disease.
"Maybe there's somebody who gained a lot of weight and became obese, or
developed diabetes in the ensuing time, or developed some other condition
that puts them at higher risk," Adalja said. "Maybe they become
immunocompromised all of that's going to play a factor."
One study focusing on U.S. veterans who are mostly older men
found reinfections in that group appeared to come with a higher
risk of death or hospitalization. But several experts cautioned
against reading too much into its early findings. (Ben Nelms/CBC)
In the elderly or in
people who are immunosuppressed, medical professionals expect to see
a range of poorer outcomes tied to severe reinfections, said Dr.
Sameer Elsayed, a professor at Western University in London, Ont.,
and a consultant on infectious diseases, internal medicine and
medical microbiology at the London Health Sciences Centre and St.
Joseph's Health Care London.
That could include
lung damage directly caused by the virus, he said, all the way to
issues such as the aggravation of "long COVID" symptoms from a prior
infection or serious secondary infections from bacteria or fungi
particularly in those individuals who require admission to an
intensive care unit.
"This latter example
is also similar to asthmatics who may require repeated
hospitalizations for something that is seemingly as simple as a
common cold," Elsayed said. "These repeated infections cause lung
damage and may potentially lead to premature death depending on
their severity, but we don't see this with otherwise healthy people
who keep getting common colds year after year."
So as we all face
the possibility of repeat COVID-19 infections through our lifetimes,
your personal risk of serious illness could change over time and
the burden of reinfections from this ever-evolving virus won't be
felt equally.
This story got "awaiting review" which means it probably got a human to
look at it and read the scores of what the AI says about the post. It does word
count. You can see here that by repeatedly mentioning Immunity, Virus and
Vaccine that the post got thru on the subject of police immunity, judicial
immunity and Prosecutional Immunity.
Unfortunately it got no likes which means the Covid article now 14 months old
is getting few readers.
Canadians suffer a virus
all right, its called Apathy, apathy and denial to the problem of a lack of
accountability and especially the immunity enjoyed by law enforcement across the
country and those who make decisions.
Its got a host of names,
examples prosecutional immunity, judicial immunity, police immunity and all them
destroy the right of Canada to call itself a society based on law. The only
vaccine is accountability that politicians don't have the courage to speak to
that need.
This post was not deleted by CBC
Virus immunity is an important
subject. Lets explore why.
This appears to be the only
story out of all the news that we can comment on. Why? because COVID is now a
non-news safe subject, the days of it being a convory to Ottawa are over.
Or are they?
The subject of that is now the
Ottawa Police who effectively ran the protest, directing them to create the
public nightmare for their own political agenda.
What we have is total immunity
that comes from a lack of accountability.
Across Canada we may have a
milder form of Covid but in North America we suffer
from a virus that is far more
dangerous, its called the lack of accountability.