While some people with Long COVID may experience a gradual improvement and return to their pre-COVID-19 state of health within a few weeks, others may have a more prolonged recovery period or experience long-lasting symptoms. The duration and severity of symptoms can vary greatly, making it challenging to predict how the condition will progress. Despite extensive investigations, the exact reasons why Long COVID symptoms persist in some people are still not well understood, which further complicates the prognosis. This article provides an overview of what is currently known about the prognosis of Long COVID, including the factors that influence the course of this condition.
Chances for full recovery after a SARS-CoV-2 infection are lower if symptoms persist for more than 1 year.
As reported in a previous blog, a recent Swiss study demonstrated that 1 in 6 unvaccinated people did not recover even two years after a SARS-CoV-2 infection. Although most participants of this large study showed continued recovery or overall improvement in health status, a small percentage experienced worsened health or alternating periods of recovery and health problems. The frequency and severity of COVID-19-related symptoms also decreased over time but around 18% of people still reported symptoms after two years.
Another key observation in this study was that many experienced an improvement in their symptoms within the first year, but the rate of improvement strongly decreased afterward. This slow recovery, which might suggest the development of long-term (chronic) health problems, has also been seen in other studies.
Presence of fatigue and neurocognitive impairment are factors that affect the recovery of a patient's overall health.
In a large French study, 85% of participants who were symptomatic two months after infection still reported symptoms one year after the beginning of their symptoms. Results also showed that one-third of people with complete recovery of symptoms experience a relapse, or reappearance, of at least one symptom within a 12-month follow-up. This study further provided interesting information on symptom patterns over time. While the frequency of some symptoms gradually decreased, such as loss of appetite, change of taste and cough, some symptoms remained common throughout the study, like word-finding problems and shortness of breath. occurrence of other symptoms even increased, including neck and back pain and paresthesia. Although people initially experience a decline in the negative effects of symptoms, there was a rapid increase in the number of people reporting an unacceptable state of the disease after six months.
Several other studies revealed similar results. Most notably, fatigue and neurocognitive impairment were identified as significant factors affecting the recovery of overall health. Some studies even found that these symptoms do not improve at all within one year, suggesting that they might persist as a chronic health issue for a certain proportion of people with Long COVID.
Younger age, male gender, milder initial symptoms, vaccination, and infection with the Omicron variant were associated with a better prognosis.
By analyzing the health outcomes over time, the Swiss study also suggested that different people had different patterns of symptoms and recovery. More specifically, participants who worsened or had symptoms throughout the study were more likely to be 65 years or older, had underlying health conditions, had post-exertional malaise (crash) and had experienced pre-existing fatigue, shortness of breath and problems with overall health.
In addition to age, a preliminary scientific report (preprint) also listed other factors that influence recovery from Long COVID. In this study, the researchers found that better recovery was associated with male gender, younger age, milder initial Long COVID symptoms, full vaccination status and infection with the Omicron variant. Notably, symptoms like brain fog and shortness of breath were associated with a lower likelihood of recovery, while memory impairment, fatigue and dizziness did not show a significant association with symptom resolution.
Another important finding is that people with previous underlying health issues had more negative health outcomes after a SARS-CoV-2 infection than people without previous underlying health issues. Indeed, some studies reported that people who recover slowly are more likely to have previous systemic diseases, for example, rheumatoid arthritis, compared to people who recovered more quickly.
Predicting the course of Long COVID is difficult due to the variety of symptoms and lack of long-term data.
Long COVID can cause various symptoms that affect different parts of the body, such as the respiratory, cardiovascular, neurological, and musculoskeletal systems. Because people with Long COVID can experience a diverse set of symptoms at the same time, it is challenging to establish a uniform method for assessing symptoms and predicting the outcome of this condition. Moreover, long-term studies are still scarce due to the limited time frame since the first observation of the Long COVID condition.
Most studies mentioned in this article used assessment scales, or questionnaires, which were not specifically validated for Long COVID. Further research is necessary to develop more accurate evaluation tools that can be used in “real-life” clinical practice. The inclusion of validated questionnaires will help better define symptoms, especially cognitive ones, which may also improve the prognosis.
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