By the end of 2022, approximately one out of every seven individuals in the United States had experienced long Covid, suggests a large-scale investigation of long Covid and symptom prevalence by academics at UCL and Dartmouth.
Having had long Covid is associated with anxiety and low mood, as well as an increased likelihood of continued physical mobility problems and challenges with memory, concentration, or understanding, according to the findings published in the journal PLOS ONE.
The risk of anxiety and low mood appeared to be lower for those who have been vaccinated, including for those who have had long Covid.
Co-author Professor Alex Bryson (UCL Social Research Institute) said: “Little is known about long Covid and its impact on health and wellbeing, but there is a growing body of evidence that many people experience persistent and concerning symptoms.
“Here, we have found that long Covid continues to affect millions of people in the US, with some groups much more affected than others. Those who have ever had long Covid remain more likely to report low mood, challenges in carrying out daily tasks, and challenges with memory, concentration, and understanding, compared to people who have never had long Covid.”
Extensive Data Analysis by Researchers
The researchers reviewed data from 461,550 people who responded to the US Census Bureau’s Household Pulse Survey from June to December 2022. They were comparing people who said they had never had COVID-19, with those who had had a COVID-19 infection without lingering symptoms, and those who currently or previously had long Covid.
In line with the World Health Organization (WHO), they defined long Covid as the continuation or development of new symptoms at least three months after the initial infection.
Findings on Long Covid Prevalence and Symptoms
The researchers found that nearly half (47%) of people surveyed reported having had COVID-19 at some point, while 14% of the total had had long Covid at some point, half of whom (7% of the total) still had long Covid symptoms when answering the survey. The findings suggest that one in three people who contract Covid-19 may end up with long Covid symptoms. The researchers caution that a limitation of their study is that it relies on people self-reporting symptoms, while some people surveyed may have had Covid-19 without knowing it.
The researchers found that people who had ever had long Covid were more likely to have a negative affect (anxiety, depression, worry, or a lack of interest in things), as well as physical mobility problems and problems dressing and bathing, all of which were self-reported by answering a questionnaire. Having had long Covid was also associated with self-reported problems with memory or concentration, and with understanding or being understood.
Demographics and Severity of Long Covid
They also found that long Covid was more common in women than men, with rates also elevated among white people, middle-aged people, and people with lower incomes or educational attainment, while being most common in West Virginia (18% of the population) and least common in Hawaii (11%).
Long Covid was also much more common among people who had severe symptoms during the initial Covid-19 infection, as 31% of people who reported currently having long Covid said they initially had severe Covid-19 symptoms, compared to only 7% of the people who had Covid-19 without developing long Covid.
They say that further research is needed to better understand how long Covid causes its various potential symptoms, while better longitudinal data is also needed to understand the potential impacts of vaccinations on long Covid risks.
Reference: “Long COVID in the United States” by David G. Blanchflower and Alex Bryson, 2 November 2023, PLOS ONE.