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New research finds that 26% of people who had COVID-19 were not fully recovered 6–8 months later. Erdark/Getty Images
  • Researchers are still studying the long-term symptoms of SARS-CoV-2 infections.
  • New data suggest that people can experience long-term symptoms of SARS-CoV-2 infections 6 months or more after infection.
  • Patients reported symptoms of fatigue, dyspnea, and depression.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.

The virus SARS-CoV-2 and the resulting disease of COVID-19 have impacted people and healthcare systems all around the world.

Initial action by governments and communities focused on not overwhelming healthcare systems, and treating the acute impact of infections in individuals.

Centering on acute problems aided in the understanding of COVID-19 and helped countries get through the initial pandemic response.

The long-term impact of COVID-19 is still unknown. Healthcare professionals are researching long-term complications of SARS-CoV-2 infections, including symptoms lingering months after a person’s initial infection with the virus.

A recent study, which appears in the journal PLOS One, reports that a quarter of the study participants had long-lasting symptoms of COVID-19 between 6 and 8 months after initial infection.

The participants had lingering symptoms of difficulty breathing and fatigue, and assessment results that indicated depression.

Understanding these long-term symptoms will help treat the people who have them.

The Centers for Disease Control and Prevention (CDC) note that those who have contracted SARS-CoV-2 may experience acute symptoms of infection, while others may be asymptomatic. Many people have gotten better within a few weeks after initial infection and do not have lingering symptoms.

However, some people experience post-COVID-19 conditions, which is an umbrella term for “a lack of return to a usual state of health following acute COVID-19 illness.”

Other terms for post-COVID-19 conditions include long COVID, long-haul COVID, and late sequelae. Some of the common lingering symptoms of SARS-CoV-2 infection include dyspnea, fatigue, cough, cognitive impairment, and pain.

Infectious disease expert Dr. William Schaffner recalls the initial impact and stress on the healthcare system brought on by the pandemic.

He told Medical News Today that the beginning of the pandemic was a period of rapid adjustment, where healthcare professionals had to learn how to take care of patients with COVID-19.

He spoke of the difficulties, such as the stretching of resources, and the shortages of personal protective equipment.

While the care of patients with COVID-19 has gotten better over time, Dr. Schaffner notes that long-term symptoms of COVID-19 and how SARS-CoV-2 causes these symptoms are areas that are still being studied.

The population-based prospective cohort study from researchers in Switzerland examined the long-term symptoms of patients who had contracted SARS-CoV-2.

The participants were residents of the canton of Zurich, Switzerland, and had a confirmed infection of SARS-CoV-2 between February 27, 2020, and August 5, 2020. Other criteria for recruitment included being at least 18 years of age, having a sufficient knowledge of German, and being able to follow the study’s procedures.

A total of 431 people participated in the study. The researchers used electronic self-reporting questionnaires to evaluate long-term effects of SARS-CoV-2 infections and collected data using the Research Electronic Data Capture survey system.

They examined the following areas 6–8 months after each participant’s initial infection:

  • the participant’s level of recovery from COVID-19
  • the presence of symptoms such as dyspnea, fatigue, depression, anxiety, and stress
  • contact the participant had with the healthcare system, such as hospitalization or doctor visits, after the period of acute illness

The participants were asked about their current health and health-related quality of life. The researchers further collected data on the participants’ sociodemographic status, comorbid conditions, risk factors, and experience during initial infection.

The study used several assessment scales in data collection, including the Fatigue Assessment Scale, the modified Medical Research Council dyspnea scale, and the 21-item Depression, Anxiety and Stress Scale.

The vast majority of the participants — 89% — had symptoms during their period of initial infection, and 19% of the participants were hospitalized due to COVID-19 for an average of 7 days.

Between 6 and 8 months after initial infection, a little over a quarter of the participants reported not fully recovering from COVID-19.

The results of the study include the following highlights:

  • 26% (111) of the participants reported they had not fully recovered from COVID-19 between 6 and 8 months after initial infection.
  • 55% (233) of the participants reported they had symptoms of fatigue.
  • 25% (96) of the participants reported some level of dyspnea.
  • 26% (111) of the participants reported symptoms of depression.
  • 40% (170) of the participants reported they had at least one visit with a general practitioner related to COVID-19 after the 4-week period of acute illness.

Lead author of the study, Milo A. Puhan, MD — who is a professor of epidemiology and public health at the University of Zurich and the director of the Epidemiology, Biostatistics and Prevention Institute — told MNT:

“Our data show that long COVID affects different people in different ways. About one quarter had not fully recovered after 6–8 months. While some individuals complained about persisting symptoms, others described symptoms of fatigue, dyspnea, and depression. We found that these outcomes appear to occur together only in [a] few participants, while the majority was affected by only one or two of these outcomes simultaneously.”

The study has some limitations, including the time frame of participant recruitment. The researchers note that those included in the study contracted the infection during the first wave of the pandemic in Switzerland.

Testing limitations, healthcare system capacities, and increased awareness of COVID-19 symptoms may have impacted sample selection and results. There was also the possibility of sample bias.

The researchers did not have baseline data of the participants’ physical and mental health prior to infection with SARS-CoV-2, making it impossible to distinguish the direct effect of COVID-19 from preexisting conditions.

Also, the researchers were unable to compare the rates of anxiety and depression in the participants with those of the general population, which was also impacted by anxiety and depression from the pandemic in general.

Finally, it is possible that the participants’ use of healthcare services was underestimated, because specialized medical and diagnostic services were not included in data collection.

Limitations and results of the study point to the need for further research.

Dr. Arturo Casadevall, immunology specialist and chair of the Molecular Microbiology & Immunology Department at Johns Hopkins Bloomberg School of Public Health in Baltimore, MD, told MNT:

“This paper adds to the increasing body of evidence that a significant proportion of people who get COVID-19 suffer from ‘long hauler’ symptoms. COVID-19 is a new disease for humanity, and we are learning about the long-term consequences of infection.”

According to Dr. Schaffner, research should focus on two main concepts moving forward.

First, research needs to center on how to care for individuals who experience long-term symptoms of COVID-19. Dr. Schaffner added that the goal for these patients would be reaching a complete — or as close to a complete — level of functioning as possible.

The other area of focus needs to be how SARS-CoV-2 causes these long-term symptoms in the body.

Prof. Puhan further noted the following regarding the usefulness of the study:

“Our findings show that a relevant proportion of individuals suffer from longer-term health effects after SARS-CoV-2 infection. It is thus crucial that healthcare systems plan services that can support those affected in their recovery accordingly. We hope that our study — together with studies from others — helps to estimate the scale and range of services that may be required now and after potential future waves of the pandemic.”

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