By now it is quite clear that COVID-19 is not always a disease that disappears quickly and leaves no trace. Millions of people in the United States and even more around the world, has long COVIDthe name of symptoms that last months or even years after an infection.
Now, a new report from the US Centers for Disease Control and Prevention (CDC) helps quantify how often COVID-19 is associated with subsequent health problems. Among U.S. adults younger than 65 who have had COVID-19, about one in five have developed a health condition that may be related to the virus, the report says. Among people aged 65 or older, about one in four.
To achieve these results, CDC researchers used electronic health records to track more than 350,000 U.S. adults who had confirmed COVID-19 cases. They tracked these people for up to a year after their diagnosis to see if they developed at least one of 26 conditions associated with post-COVID-19 disease – including heart disease, respiratory problems, asthma, kidney disease, neurological conditions, diabetes and mental disorders. In comparison, they also tracked a group of 1.6 million American adults who had not had COVID-19 but who sought medical attention for other reasons during the study period.
From that comparison, it was clear that COVID-19 survivors had an increased risk of developing almost all of the 26 conditions. The most dramatic risk differences between COVID-19 survivors and the general population were in the development of respiratory symptoms and pulmonary embolism, a type of blood clot that can lead to shortness of breath and chest pain. People who had had COVID-19 were about twice as likely to develop both diseases.
There were some limitations to the data. The researchers used a specific electronic medical record network, so the patient base may not be fully representative of the American population. It is also possible that physicians looked more closely at the analyzed conditions in COVID-19 survivors than in those who had not had the virus, or that some people had undiagnosed conditions before they became infected. (People with a documented, recent history with one of the 26 conditions were excluded from the study.) The researchers also did not take into account a person’s COVID-19 vaccination status, and the data collection only ran until November 2021, so it is impossible to say , where newer COVID-19 variants such as Omicron fit into the picture.
Yet the study provides even more evidence that COVID-19 can cause problems that last much longer than an acute infection does. Although symptoms such as cough, fever and fatigue disappear within a few days, the virus can leave a lasting mark in ways that are not immediately apparent.
This is especially a cause for serious concern given how contagious the currently circulating variants are. Nearly 60% of the U.S. population had been infected by February, according to CDC estimates, and that number is almost certainly much higher now. “As the cumulative number of people who have ever been infected with SARS-CoV-2 increases, the number of survivors suffering from post-COVID conditions is also likely to increase,” the authors of the new report write.
These conditions can be severe or even disabling –some with Long COVID have had to leave their jobs or drastically change their lifestyle – and it is not always possible to predict who will be affected. The best way to avoid post-COVID complications, experts often say, is to avoid catching the virus in the first place, and to be vaccinated and boosted if you do.
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