A fifth of coronavirus patients without symptoms develop long Covid, study finds

  • Although the number of new cases is dropping as people get vaccinated, long-haul Covid remains a threat to public health
  • People experience mental health issues like anxiety and depression in addition to physical problems, such as trouble breathing
Agence France-Presse |

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Even after recovery, long-haul coronavirus symptoms can persist for some people.

Almost a fifth of Covid patients without symptoms went on to experience conditions consistent with long Covid a month after their initial diagnosis, according to a recently-published study.

The analysis by non-profit FAIR Health consisted of insurance claims from 1.96 million Americans - the largest population of patients ever studied for long Covid - from February 2020 to February 2021.

“Even as the Covid-19 pandemic wanes, long-haul Covid persists as a public health issue affecting many Americans,” said FAIR Health’s president Robin Gelburd.

“The findings in our new study shed significant light on this emerging issue for all individuals who have long-haul Covid, as well as for policy makers, providers, payors and researchers.”

“Long Covid” refers to symptoms of the disease that persist more than four weeks after being diagnosed.

The study found that across all ages, the most common post-viral conditions were, in order of frequency: pain, breathing difficulties, high cholesterol, general discomfort and fatigue, and high blood pressure.

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Nineteen per cent of asymptomatic Covid patients experienced long Covid symptoms 30 days out from their initial diagnosis; the figure grew to 27.5 per cent of Covid patients who were symptomatic but not hospitalised, and 50 per cent of those who were hospitalised.

The order of most common long Covid conditions varied by age group - for children, intestinal issues replaced high cholesterol as the third most frequent issue.

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Among the four mental health conditions evaluated after 30 days, anxiety was the most common, followed by depression, adjustment disorders and tic disorder.

The biggest drawback of the new study is it lacks a control group of people who never got Covid, which would help determine the extent to which Covid caused the conditions as opposed to being coincidental.

The causes of long Covid, which is also known as long haul Covid, post-Covid syndrome or post-acute sequelae of Covid, remain unknown, though there are a few theories.

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