It is relatively common and reports at least one symptom 6 months after recovery from COVID-19 infection. Fatigue, muscle weakness, and insomnia are the most commonly reported symptoms.
An exaggerated immune system response, cell damage, or the physiological consequences of a critical illness may contribute to the development of long COVID-19. But it’s not clear exactly what causes it, or why some people seem to be more susceptible.
A growing body of evidence has implicated the gut microbiome, which hosts the trillions of bacteria, fungi, and other microbes that inhabit the digestive tract in COVID-19 severity.
Given that the gut has a major role in immunity, a disordered immune response to COVID-19 infection, induced by resident microbes, may affect the recovery process too.
Researchers, therefore, wanted to find out if the makeup of the gut microbiome might be linked to long COVID, defined as at least one persistent symptom 4 weeks after clearance from the body.
They tracked changes in the gut microbiome of 106 patients with varying degrees of COVID-19 severity, treated at 3 different hospitals between February and August 2020, and in a comparison group of 68 people who didn’t have COVID-19, over the same period.
They did this by analyzing participants’ stool samples. Among the 106 patients with COVID-19, stool samples were collected on admission (68), and again after 1 month (64) and after 6 months (68). Stool samples were also collected from 11 patients 9 months later.
Researchers checked for the presence of the 30 most commonly reported long COVID symptoms 3 and 6 months after initial COVID-19 infection. Aerobic capacity and endurance, an indicator of long COVID, was also measured in a 6-minute distance walk test.
The average age of the patients with COVID-19 infection was 48; just over half were women. Most (81%) had mild to moderately severe infection; 25 were treated with antibiotics.
Long COVID was reported in 86 (81%) of these patients at 3 months and in 81 (76.5%) at 6 months. The most common symptoms at 6 months were fatigue (31%), poor memory (28%), hair loss (22%), anxiety (21%), and sleep disturbances (21%).
There were no significant differences in potentially influential factors, such as age, gender, the prevalence of underlying conditions, use of antibiotics or antiviral drugs, or COVID-19 severity between patients with and without long COVID, 6 months after initial infection.
Among the 68 patients with COVID-19 whose stool samples were analyzed at 6 months, 50 had long COVID. While initial viral load wasn’t associated with long COVID, their gut microbiome differed from that of patients without long COVID and those who hadn’t had COVID-19 infection.
Among the bacteria species found in patients with long COVID, 28 were reduced and 14 were enriched both at hospital admission and 3 and 6 months after hospital discharge.
On the other hand, the gut microbiome of those who didn’t develop long COVID showed only 25 changes in bacteria species at hospital admission, and this recovered completely after 6 months.
Eighty-one bacterial species were associated with different categories of long COVID and many species were associated with more than two categories of persistent symptoms.
Similarly, several ‘unfriendly’ bacteria species were associated with poorer performance on the 6-minute walk test among those with long COVID.
This is an observational study, and as such can’t establish cause. And only a small number of participants were included in the study. But the findings echo those of other research, implicating a disordered gut microbiome in a range of long-term conditions.
Considering the millions of people infected during the ongoing pandemic, the study findings are a strong impetus for consideration of microbiota modulation to facilitate timely recovery and reduce the burden of post-acute COVID-19 syndrome.
Source: Medindia
