Most people got long COVID-19 from mild cases. It’s important to note that even in mild cases, COVID-19 can have severe and long-lasting consequences for a person’s health. This is one of the main takeaways from our international study on long COVID-19, or long COVID, published in the Journal of the American Medical Association.
The SARS-CoV-2 virus causes COVID-19, and “long COVID” occurs when symptoms persist or emerge more than three months after the initial infection. There is no other explanation for the persistence of these symptoms after at least two months.
We found that 90% of those with long-term COVID had only mild illness with COVID-19 at first. However, after developing long-term COVID, the typical person experiences various symptoms, including fatigue, shortness of breath, and cognitive problems like brain fog. The health consequences of these symptoms were comparable to those of traumatic brain injury. Women in our study had a risk of developing long COVID two times that of men and four times that of children.
More than a million people in 22 countries reported having COVID-19 symptoms, and we analyzed data from 54 studies covering those people. We tallied the number of people with COVID-19 who developed clusters of new long-COPID symptoms and analyzed the correlation between these factors and hospitalization for COVID-19.
When comparing people who had not been hospitalized for COVID-19 with those who had, we discovered that those who had been admitted showed a higher risk of developing long COVID and experiencing more prolonged symptoms. However, many more cases of long COVID have arisen from these milder cases despite the lower risk, as the vast majority of cases of COVID-19 do not require hospitalization. In our study, we found that nearly one out of every seven people with long COVID still had symptoms a year later, and it is unknown how many of these cases may become chronic.
The results of our comprehensive, cross-national study of this condition shed light on the potential high human and economic costs of long-term COVID across the globe. Many of those who have it are adults in the prime of their careers. People’s incomes, livelihoods, and homes could all be jeopardized if they were out of commission for an extended period. Long-term COVID can make it difficult, if possible, for parents or carers to continue providing for their children.
Long-term COVID is a significant factor in the current labor shortage due to its widespread and severe impact on people’s ability to work. The long duration of COVID could also contribute to the disproportionate impact on women during the economic downturn.
According to us, researchers and research funders should prioritize the development of effective and cost-effective treatments for people with long-term COVID. Although long-term CMV clinics have opened to fill this gap in care, the treatments they offer are often unreliable and can be pretty pricey.
Some symptoms of long-term COVID go away, only to come back, and new symptoms may even appear. But scientists have yet to determine why.
Although we only looked at the three most common symptoms of long COVID that we found to be problematic for daily life, other symptoms can include a loss of smell or taste, insomnia, gastrointestinal problems, and headaches. However, these supplementary symptoms typically co-occur with the primary symptoms for which we calculated prevalence rates.
What exactly causes long-term COVID in some people is still a mystery. Why, for instance, do some people have a higher risk of developing the condition than others, and how exactly do risk factors like smoking and obesity play a role in this? Is there a difference in the potential for long-term COVID after a second infection with SARS-CoV-2? In addition, it is not known how long-term protection against long COVID varies after vaccination or boosting against COVID-19.
The COVID-19 variants also raise new questions. The omicron variant is less lethal than previous strains by the research community. The initial data suggests that the risk of long-term COVID is lower with omicron than with earlier songs, but this hypothesis needs to be confirmed by more extensive research.
Before omicron became dominant, most people in our study population were infected with the deadlier circulating variants. To better understand the long-term effects of COVID-19 after omicron’s arrival, we will continue to expand upon our research on long COVID as part of the Global Burden of Disease study, which estimates deaths and disabilities from all diseases and injuries in every country around the world.