May 26, 2023: A recent study involving nearly 10,000 Americans, including COVID-19 survivors, has provided crucial insights into long COVID, and related post-infection conditions that can affect various tissues and organs.
Published in JAMA and supported by the National Institutes of Health (NIH) through the Researching COVID to Enhance Recovery (RECOVER) initiative, this study aims to understand why some individuals develop persistent symptoms after COVID-19 and explores methods to detect, treat, and prevent long COVID.
Long COVID can persist for months or even years after recovering from COVID-19. Notably, long COVID was found to be more prevalent and severe among those infected before the emergence of the Omicron variant in 2021.
Long COVID symptoms
The research team examined data from 9,764 adults, including 8,646 who had previously contracted COVID-19 and 1,118 who had not. Assessing over 30 symptoms across multiple body areas and organs, the researchers identified 12 symptoms that distinguished individuals with long COVID from those without: post-exertional malaise, fatigue, brain fog, dizziness, gastrointestinal symptoms, heart palpitations, issues with sexual desire or capacity, loss of smell or taste, thirst, chronic cough, chest pain, and abnormal movements.
To quantify and differentiate long COVID, the team developed a scoring system based on these patient-reported symptoms. By assigning points to each of the 12 symptoms, they were able to calculate a score for each patient, facilitating the identification of individuals with long COVID. Furthermore, the researchers observed that certain symptoms tended to co-occur, leading to the definition of four distinct subgroups or “clusters” with varying impacts on health.
Analyzing a subset of 2,231 patients who contracted COVID-19 after December 1, 2021, when the Omicron variant was circulating, approximately 10% of them experienced long-term symptoms or long COVID after six months. However, it is important to note that these results are based on survey data and require validation through further laboratory tests and imaging.
With over 100 million Americans having contracted SARS-CoV-2 to date, the federal government’s Household Pulse survey estimates that approximately 6% of those infected continue to experience symptoms associated with long COVID. More than 200 symptoms have been identified and associated with long COVID by patients and researchers alike.
“This study represents a significant step in defining long COVID beyond individual symptoms,” stated Dr. Leora Horwitz, study author and co-principal investigator for the RECOVER Clinical Science Core at NYU Langone Health. “This approach, which may evolve over time, will serve as a foundation for scientific discovery and treatment design.”
A negative test for Covid-19 does not end the infection. Some people continue to suffer from the underlying effects of the disease, which manifests in the form of poor health. People suffer from anxiety and sleep difficulties, heart arrhythmias and blood clots.
“Viruses have long-term consequences,” said Dr Ziyad Al-Aly to LA Times. He has studied the downstream health effects of an encounter with the SARS-CoV-2 virus.
Studies show that around 10–20% of people infected by SARS-CoV-2 may go on to develop symptoms that can be diagnosed as long COVID. Although exact numbers of those living with the condition are uncertain, it is believed that more than 17 million people across the WHO European Region may have experienced it during the first two years of the pandemic (2020/21).
A study by the Centers for Disease Control and Prevention shows that long COVID was the reason for 3,544 deaths in the United States between January 2020 and June 2022. “A lot of people think of long covid as associated with long-term illness,” said Farida Ahmad, a health scientist at the Centers for Disease Control and Prevention while speaking about the effects of long Covid and lead author of the study. “This shows it can be a cause of death.”
The percentage of people who have had COVID and currently report long COVID symptoms declined from 19% in June 2022 to 11% in January 2023, according to the latest US government figures. Another study done in Israel found that most symptoms of long COVID resolved within a year, although that study was limited to people with mild illness.
The National Institutes of Health published the findings on May 25, 2023.