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For nearly three years, scientists have been working tirelessly to uncover the mysteries of COVID-19 — while an increasing number of people struggle with its life-changing symptoms.
it is formally known as Situation after COVID-19A group of 200 or more medical issues that can persist for months after an initial infection, ranging from fatigue to shortness of breath to a feeling of “brain fog.”
For some, prolonged COVID can lead to a frustrating few months. For others, it leads to debilitating health effects that never seem to resolve. That range of possibilities leaves many sufferers wondering: How long does COVID really last?
A new, large-scale study out of Israel is the latest research to dig into the spectrum of symptoms, who is affected, and for how long.
Published in the British Medical Journal on WednesdayThe peer-reviewed research looked at nearly two million medical records, and matched nearly 300,000 people who had a confirmed infection with another 300,000 who did not test positive for SARS-CoV-2.
The researchers found that a range of health problems persisted for several months following a mild case of Covid, but resolved within the first year after infection.
Some symptoms were more likely to persist, including weakness and difficulty breathing.
“There are patients who are experiencing COVID symptoms for a year long, and their lives change, and they are suffering – we know this,” said a senior researcher at the KI Research Institute in Kafr Malal, Israel. Doctor. Metal Bivas-Banita said.
“But when we look at this large population and we look at their medical records, we see that a small number of symptoms occur, and we see that they subside over time.”
look | New research shows that most long COVID symptoms clear up within a year:
Shortness of breath, weakness is likely to persist
The research looked at dozens of different health effects associated with COVID over the long term, including rash, dizziness, hair loss, heart palpitations, chest pain, stomach pain.
The team divided their findings into two time-frames: the first three to six months after infection and the next six months.
Most persistent post-Covid health issue? According to the study, difficulty in breathing.
But this was far from the only common complaint. Others, including hair loss, persisted in the early months following an infection, the findings show, with breathing problems, weakness, dizziness and a feeling of brain fog being among those that persisted for up to a year.
“He also saw [being] said Dr. Angela Cheung, a clinician-scientist at the University Health Network, who has been treating Covid patients for a long time at a clinic in Toronto.
This isn’t the first study to suggest that vaccination can reduce long-lasting COVID risks. Earlier American research, Published last May in the journal Nature Medicinefound that vaccination can reduce the likelihood of long-term COVID by about 15 percent.
Searches exclude omicron
In fact, research – like all scientific studies – has its strengths and weaknesses.
The large amount of medical records gave the team the ability to compare people with SARS-CoV-2 infection to an uninfected control group, matching subjects based on factors such as their age and pre-existing health conditions. Doing so helped the team identify which symptoms were most likely to be caused by the infection.
“You want to look at the difference that COVID adds,” said Barak Mizrahi, another senior researcher at the KI Research Institute who worked on the study.
On the other hand, her colleague Bivas-Banita stressed that the use of medical records could also mean that the results underestimated people with unresolved health issues, because those who did not seek medical attention were included. had not been. (The researchers also excluded hospitalized patients to focus on milder infections.)
In the paper, the researchers also noted that there may have been under-reporting of symptoms in the post-study period.
And importantly, the study period only spanned from March 2020 to October 2021, so the findings do not include the currently circulating Omicron variant that sparked a major wave of cases in Canada in early 2022.
“This study was mainly looking at the Delta version time frame, not Omicron,” Cheung said.
‘People improve with time’
While the data may be first in the pandemic, several Canadian longtime COVID researchers – who were not involved in the study – say it adds another piece to the puzzle.
“Yes, it’s retrospective, yes, it’s from medical records, but it’s showing us that people improve over time, which is an important thing for people to remember,” said Cheung, who shared some of his Patients have also been added. With post-COVID health effects for more than two years.
Most important, says McMaster University immunologist Manali Mukherjee, the Israeli team aimed to use a control population of people who were uninfected within a larger sample size.
“This is exactly the kind of study you need,” she said.
The findings follow from Mukherjee’s own research, Published in the European Respiratory Medicine last fall journal,
Using a very small sample of about 100 patients in Canada, Mukherjee’s team showed that about three-quarters of people infected with SARS-CoV-2 recovered within a year, regardless of the severity of their disease. However, while others suffered from ongoing symptoms of cough, fatigue and whooping cough. Difficulty in breathing
But that study was also limited by the small sample size and, like the Israeli paper, only looked at the time period before Omicron’s arrival.
Mukherjee’s research also found that patients with persistent symptoms had antibodies associated with autoimmune diseases, and increased levels of cytokines — small proteins that are an important part of the body’s cellular communication network — that can trigger inflammation.
In a call with CBC News, Mukherjee — herself a long-time Covid sufferer — said one of several possible mechanisms being explored to explain the range of prolonged Covid symptoms is, While others are looking at potential ripple effects from issues like small blood clots,
“The reason you have so many different theories is because you have so many different presentations of it,” she said.
Long COVID likely to fall
Multiple presentations, varying time frames, and a range of severities – all of these factors make the study of prolonged COVID a challenging proposition.
The new Israeli research specifically avoided any breakdown of what percentage of people actually recover within a year, and what percentage doesn’t. Doing so, the researchers said, was not the goal, nor is it something easy to do given the broad spectrum of post-Covid illness.
So far, there’s a big ballpark of how many people are being affected. The World Health Organization (WHO) maintains about 10 to 20 percent of people A person infected with SARS-CoV-2 may develop symptoms that can be diagnosed as COVID for a long time. Other estimates over the years range from a small percentage of cases to as high as 30 or 40 percent.
As previously reported by CBC NewsA growing body of research assures that long-term COVID rates are now lower than previously thought, possibly thanks to increasing levels of immunity through vaccination.
Early findings using self-reported, app-based data from a team in the UK found Decreased odds of long COVID With the Omicron version compared to the Delta.
Similarly, a Canadian COVID survey showed that 26 per cent of adults reported at least three months of post-infection symptoms before December 2021, Which reduced to 11 percent after December 2021 In both cases, however, the self-reported data come with limitations, and neither includes a year or more of patient reports to show long-term effects.
Much remains to be understood about this situation, with WHO calling for ongoing global funding and research.
In response to a question from CBC News on Wednesday, Dr. Maria Van Kerkhove, WHO’s technical lead for COVID-19, said “much work remains to be done in this area, including validation, research and rehabilitation.”
Katie McLean, a 44-year-old Vancouver resident who has long battled an array of COVID symptoms since catching the virus in September 2020, hopes that while any study shows that the majority of people recover, researchers should be aware of the condition. Will not stop studying. ,
More than two years after she first fell ill, McLean still struggles with fatigue and weakness, relies on a walking stick, and has not been able to return to work.
“My biggest concern would be if the pandemic continues and more and more people end up in my shoes – and there is no answer,” she said.