The possible complications of Covid-19, generically referred to as Long Covid, are one of the most popular topics and one of the most feared by the population. However, there is still not much information about the prevalence of these problems, the risk factors and the ability to predict these types of symptoms at the beginning of the disease.
A study now released by Nature looked at 4,182 Covid cases with long-term symptoms – 558 (13.3%) participants reported symptoms for more than 28 days; 189 (4.5%) for more than 8 weeks and 95 (2.3%) for more than 12 weeks.
The presence of these symptoms (fatigue, headache, total or partial loss of smell, dyspnoea, among others) was more frequent as age and body mass index increased, and in females.
According to the research, having more than five symptoms during the first week of illness was associated with long Covid. This pattern was similar in the three countries included in the study (UK, USA, Sweden), in both sexes and across all age groups.
At both the four-week and eight-week thresholds, patients with prolonged Covid symptoms “were consistently older, more likely to be female, and more likely to have required hospital assessment”
Patients with symptoms after 28 days “had multisystem disease from the start, supporting the need for holistic care“. Although asthma has not been reported as a risk factor for hospitalisation in some studies, “its association with long Covid (>28 days) justifies further investigation“.
“Analysis of the pathophysiological drivers underlying the risk factors for long Covid identified here is a critical next step.”
“Moreover, this method could help determine at-risk groups and be used to target early intervention trials and clinical service developments to support rehabilitation in primary and specialist care to alleviate long COVID and facilitate timely recovery.”
Study limitations
The document points out that:
“While this study provides insights into the clinical presentation of long COVID, there are limitations and any generalization should be considered carefully.”
The study was based on data from the COVID Symptom Study, a mobile app on which people recorded daily information about their health status and symptoms, as well as the results of any Covid-19 test. It combined data from three countries: UK (88.2%), US (7.3%) and Sweden (4.5%)
Users were disproportionately female, and those over 70 years of age were under-represented, “which could increase or decrease our estimate of the prevalence and duration of long Covid“. The data are based on PCR tests.
In fact, this study has numerous limitations including having a non-randomly selected sample, no control (and/or placebo) group and most of the symptoms reported being non-specific to the disease.
More robust studies are needed, particularly to compare with the long-term effects of other respiratory infections.
To access the full context of the study click here
