A study published on Friday (19) in the scientific journal JAMA Network Open brought even more concern to the pandemic universe: nearly a third of people with covid-19 develop persistent symptoms up to nine months after diagnosis, even in initially mild cases.
Conducted by researchers at the University of Washington, the work analyzed information from 177 people in the Seattle area with confirmed covid-19 infections. Although the population is small, follow-up from three to nine months after diagnosis (mean six months) is the longest time ever performed in the US.
The majority of participants, 150 people or 85% of the study group, had a mild case of covid-19 and did not need to be hospitalized; 11 participants (6%) were asymptomatic and 16% were hospitalized. The results showed that 32.7% of patients with mild cases and 31.3% of those hospitalized reported at least one persistent symptom that lasted at least three months after diagnosis.
Persistent symptoms of covid-19
Among the persistent symptoms reported by study participants, the most common were fatigue (13.6% of occurrences) and loss of smell or taste (13.6%), according to the authors. Of the total, 13% of patients experienced other types of symptoms, including the mysterious “brain fog” as well as muscle pain, difficulty breathing and coughing.
A total of 51 outpatients and hospitalized patients (30.7%) confirmed a worsening in their health-related quality of life (HRQOL) when compared to the evaluative baseline. Four healthy participants and asymptomatic patients (12.5%) reported improvement in HRQOL, while 14 patients (7.9%) complained of negative impact on at least one activity of daily living (ADL).
One of the findings of the Seattle study was “that the health consequences after covid-9 extend far beyond acute infection, even among those with mild illness.” Of the 30% who reported a deterioration in their HRQoL, 8% claimed difficulties with daily tasks, especially household chores.
Impacts on people’s daily lives
The lead author of the study, Dr. Helen Chu, stated in a statement that “you may do well at first, but then, over time, you develop symptoms that are quite disabling in terms of fatigue.” According to this American immunologist, the team also intends to analyze blood samples from patients with covid-19 to clarify a series of questions that are still unanswered.
What is still unclear to researchers is why some people develop these more persistent symptoms, sometimes called “long covid.” “Is it some kind of immune activation, some kind of inflammation or the development of autoimmunity?” Chu.
Even acknowledging that the small sample size can constitute a limitation to the validity of the research, the researchers consider that “even a small incidence of long-term debility can have enormous economic and health consequences”, especially in a universe that is approaching 63 million individuals.