The Long Haul: What Do We Know About Post-COVID Condition?

Long Haul Covid

Long COVID could affect as many as 30% of patients, or 500,000 Canadians. Photo: Stephen Lux/Getty Images

Mima Staikova doesn’t know how she got COVID-19. The University of Toronto lecturer barely left her house in the spring of 2021 as she prepared an online chemistry course she had to teach in May. Her only trip outside was to the dentist, where everyone was fully vaccinated, only one patient was allowed in at a time, and the technicians were masked, gloved and gowned.

Three days later, she spiked a fever that hovered around 40 C for a week. “I was kind of in and out of my senses,” she says. “I could barely get up to get a bit of water.” Staikova also experienced muscle pain, a bad headache and her digestion was a disaster. After a trip to emergency — and almost three weeks from the onset of her symptoms — Staikova, who is in her late 50s, was diagnosed with COVID-19 only days before she was scheduled to receive the first vaccine. Now, six months later, she was still struggling with the after-effects.

Post-COVID condition (PCC), or long COVID as it’s commonly known, is generally believed to affect at least 10 per cent of COVID patients, about 170,000 people in Canada. But Dr. Angela Cheung, an internal medicine specialist at the University Health Network in Toronto, who is co-leading a COVID-19 study, thinks long COVID could affect as many as 30 per cent of patients, or 500,000 Canadians.


Symptoms and Risk Factors


Symptoms start within a few months of infection and last at least two months, although Cheung, who is a professor at the University of Toronto and its KY and Betty Ho Chair in Integrative Medicine, has documented cases that lasted for more than a year. “It’s not the majority,” she says, “but with the scale of the COVID-19 pandemic, there will be a fair number in that situation.” Patients typically report fatigue, cognitive changes like brain fog, shortness of breath, headaches and heart palpitations.

Among the risk factors for developing PCC, according to an October 2020 study of 4,182 people from King’s College London, are being older, female, asthmatic and/or overweight. Researchers there also concluded that the intensity of the original infection and the number of symptoms appeared to have some bearing on who would go on to develop long COVID. 

Cheung has been leading a longitudinal cohort study that began in July 2020 and has enrolled almost 1,740 COVID-19 patients and caregivers in Vancouver, Calgary, Winnipeg, the Greater Toronto Area, Hamilton, Niagara, Montreal and Sherbrooke. There is a mix of cases: Some were in the ICU, some were hospitalized but not admitted to intensive care, and some were sick at home. 

The goal of the study, called CANCOV, is to evaluate the short- and long-term effects of COVID after diagnosis and assess the sociodemographic, clinical and multi-omic factors associated with these outcomes, including long COVID and death. Cheung and her co-investigator, Dr. Margaret Herridge, a specialist in pulmonary medicine and critical care at UHN in Toronto, hope to have 2,000 participants when the trial ends in March 2022, although she has requested a year’s extension. Some patients have been monitored since the study began. 


More Women Suffer From Long COVID


Patterns have already emerged. Men tend to get sicker and are hospitalized with COVID more often than women, but more women suffer from PCC, says Cheung. While women of all agesand men as well, for that matter experience long COVID, a great number are in the “40- to 60-something-ish range,” she adds. 

“We don’t totally understand how perhaps hormones and hormonal changes may modulate all of this, and we’re trying to look into this as well,” Cheung says. “We do know that COVID sometimes affects menstrual periods.” 

Staikova is still not back to normal. The fever, which lasted a month, is gone, but the headaches randomly return. While she didn’t lose her sense of smell, she had a multi-coloured coating on her tongue for two months, and everything tasted sweet or salty. Her hair is falling out, she can’t run anymore because she coughs too much, and she fears she won’t be able to sing in her choir anymore because her voice still isn’t as strong as it was before COVID. 

“I’m not as productive as I used to be,” says Staikova. “I used to be able to keep in mind what I needed to do, but that causes mental exertion now.” Earlier in the post-infection phase, it took Staikova days to reconstruct solutions to a quiz she’d given her students pre-infection. “Basically it was like starting from the beginning.” 

The episodic nature of long COVID means that people can relapse into “post-exertional malaise” if they push themselves too hard, too quickly — but the definition of “push themselves” can vary a lot. “Exertion may not be just physical; it can be cognitive or emotional,” Cheung says. “One patient told me she can’t even watch movies that are too emotionally involved because it exhausts her.”

Researchers like Cheung will get a better picture of PCC in Canada now that the World Health Organization has an official definition, and the International Classification of Diseases has given PCC a code, which is used in health care to identify and group diseases, injuries, adverse side-effects and more. With PCC now coded, all cases will hopefully be documented as such, whereas before they might have been lumped in with COVID-19 or by specific symptoms. “Without a code, it’s really difficult to get a handle on how many people are affected and how much health care they use,” Cheung explains. “So that’s an important piece.”

Based on the behaviour of other post-viral conditions — particularly mononucleosis and SARS1 — as well as what Cheung has seen in study participants in the past year and a half, she is confident most people with long COVID will get better. That said, it may take longer for patients released from the ICU, and some people may never fully recover.

For the majority, however, “it takes resting and pacing and doing breathing exercises and a few other things,” Cheung says. “It takes time.”