Covid-19 can linger in the gut for up to seven months - new study

For millions of Covid-19 survivors, the common question is always how long will the symptoms and the viral load last?

While for many with mild illness symptoms the virus often clears within a few weeks, a new study by US researchers has revealed that it may linger in the gut up to seven months after Covid-19 symptoms have disappeared. 

Researchers from Icahn School of Medicine at Mount Sinai in New York City detected the virus in some patients long after their symptoms had disappeared, including those who never had gastrointestinal symptoms such as diarrhoea, vomiting and nausea.

Speaking at the virtual Conference on Retrovirus and Opportunistic Infections this week, lead researcher Minami Tokuyama said only 37% of patients who had traces of the virus in their small intestine had gastrointestinal symptoms during Covid-19 acute infection. In 46% of the patients the virus could not be detected in the gut.

Despite the presence of the virus, inflammation in these patients remained mild or undetectable in most cases. Out of 29 patients who formed part of the study, only one patient had inflammation and this could be attributed to transplant rejection rather than Covid-19.

Tokuyama said in two patients where virus was present at three and four months, additional biopsies were obtained at seven and six months, respectively. Viral antigen was persistently detected in both patients and both patients were nasopharyngeal swabbed negative for all procedures.

Another study that was presented at the conference showed that an overactive response to Covid-19 infection can result in a serious lung inflammation, which can lead to disruption in gut barrier integrity. Such interference, according to researchers from the Wistar Institute in the US, could increase the permeability to the gut or cause a leaky gut, further fuelling severe Covid-19 infection.

Lead researcher Dr Leila Giron said this week that Covid-19 was associated with a molecule, zonulin, which is not only a physiological marker, but also the driver of intestinal permeability. This molecule is also associated with distribution of bacterial and fungal products into the blood stream.

Researchers also found that patients with severe Covid-19 infection had several metabolites, including elevated levels of succinate acid that is associated with microbiome disturbances, and mostly found in patients with inflammatory bowel disease such as ulcerative colitis and Crohn’s disease.

“Our data provide multiple layers of evidence that a previously unappreciated factor with significant clinical implications, disruption in gut barrier integrity, is a potential force that contributes to Covid-19 severity.

“Our results do not imply that microbial translocation is the primary trigger of severe Covid-19, as this is a complex clinical syndrome that likely embodies multiple pathophysiological pathway. However, the robust literature indicating that disrupted intestinal barrier and microbial translocation fuel inflammation during respiratory disease supports our hypothesis and is consistent with our findings,” said Giron.

Meanwhile, two separate studies, in the US and the UK, have shown higher rates of hospitalisation for Covid-19 among those living with HIV and other comorbidities, including diabetes, hypertension and heart disease.

Research led by Jing Sun from Johns Hopkins Bloomberg school of public health specifically focused on HIV-positive people who had received an organ transplant.

They found that HIV-positive people who had contracted Covid-19 were likely to be hospitalised and often required mechanical ventilation compared to their HIV-negative counterparts. About 509,092 patients were included in this analysis, of which 2,932 were living with HIV alone. About 4,633 were HIV-negative and had received organ transplants vs 111 HIV-positive organ transplant recipients.

Researchers concluded that HIV-positive patients were 32% more likely to be hospitalised than those who were HIV-negative. For HIV-positive people who were also organ transplant recipients, the risk of hospitalisation increased to 65%. Among people living with HIV with history of cardiovascular diseases, hospitalisation was significantly higher than those without cardiovascular problems.

A study led by Dr Ming Lee of Guy’s and St Thomas’s Hospital in London observed the impact of HIV on Covid-19 outcomes in people living with HIV. The study compared those with HIV with those who were HIV-negative.

After admission to hospital, people with HIV were 43% less likely to have improved by at least two points on the Covid-19 severity scale, within the first 28 days of hospital admission. People with HIV spent an average of 10 days in hospital compared to 7.5 days for the control group.

TimesLIVE