As if the panic and stress caused by the COVID-19 pandemic and the consequent lockdown were not bad enough, Bollywood star Amitabh Bachchan has recorded and posted an entire video centred around the claim that flies can spread the coronavirus if they come into contact with infected human faeces.

If only the celebrated actor had bothered to acquaint himself with the scientific literature before spreading misinformation!

Let’s start with the unvarnished facts. A scientific letter was published last week in The Lancet Gastroenterol Hepatol Journal in which researchers reported results of the presence of the new coronavirus in respiratory and faecal samples. (The virus’s presence was confirmed by a real-time reverse-transcription polymerase chain reaction (RT-PCR), a time-consuming but reliable method.)

The researchers collected respiratory and faecal samples from 74 of 98 patients infected with COVID-19 (76% of the patient group). Faecal samples from 45% of these patients were negative for the virus but their respiratory swabs tested positive for 15.4 days from the onset of the first symptoms. Of the 55% of patients whose faecal samples tested positive, the respiratory swabs also tested positive for 16.7 days from the onset of the first symptoms. Their faecal samples continued to test positive for 27.9 days after the first symptoms showed.

Thus, patients infected with COVID-19 had the coronavirus in their stools for an average of 11 days more than in their respiratory swabs. However, 45% of patients did not have COVID-19 in their guts (thus the negative faecal samples).

(The virus enters the gastrointestinal tract using ACE2 receptors present in the stomach, the duodenum and the rectum.)

Researchers have made some crucial observations worth noting here: a) the presence of gastrointestinal symptoms was not associated with faecal viral positivity; b) the severity of disease was not associated with extended duration of the virus in faeces; and c) there was an association of faecal virus with anti-viral treatment.

The authors of the letter suggested that public health officials should routinely test stool samples with RT-PCR even after a patient’s respiratory samples have turned negative. However, they also conceded that they couldn’t find out whether the virus in the stool was still viable, at least based on RT-PCR tests, and that they knew zero cases in which the virus had been transmitted through faecal matter. So this, they concluded, “might suggest that infection via this route is unlikely in quarantine facilities, in hospitals, or while under self -isolation.”

Obviously we need more studies to determine the viability and infectivity of COVID-19 in faeces. But based on this scientific letter, we can draw a few conclusions. For example, the new coronavirus is present for longer in faeces than in the respiratory tract, but we don’t know much about how viable and infective the virus in the faeces is. Crucially, the letter does not mention transmission of COVID-19 by flies anywhere.

A news report in the Hindustan Times on March 26 quoting a famous Bollywood actor therefore comes as a surprise. “If the house fly sits on [infected] faeces and then on some food articles, [the flies] can spread the disease,” the newspaper quoted Amitabh Bachchan as saying in a self-recorded video. “So it is very important that we start a people’s movement against this, just like we did under the leadership of the Prime Minister to make the country open-defecation-free.”

While the newspaper’s report links to a study in The Lancet, Bachchan’s claim about flies and the virus being transmitted through faecal matter is not based on any peer-reviewed scientific paper.

The reference provided by Hindustan Times is a comment on recommendations for stool transplants from prospective donors, who it says should be screened for COVID-19 symptoms within the previous month, for travel to areas infected by COVID-19 and/or for close contact with an infected person

The comment in turn refers to a study (yet to be proofread) with 73 patients infected with COVID-19. Of them, about half were stool-positive for 1 to 12 days. About 23% of the patients continued to have positive stool samples even after the respiratory samples had turned negative. The authors of this study had noted they thus had evidence of gut infection and that the faecal-oral transmission route is “possible”. However, they keep off from making specific claims about the virus’s infectivity by this route.

The coronavirus global pandemic has brought the planet to a near-standstill. Economies across the world have been battered even as scientists are scrambling to provide answers. There have been mixed signals about different aspects of the new disease in almost every country. The people are understandably under duress – and it is precisely in such times that we have to hold our nerves. It is imperative that we keep our wits about us and gather information from peer-reviewed publications in legitimate scientific journals. Failing that, the homepage of the Union ministry of health lists daily bulletins on the various dos and don’ts regarding the new coronavirus.

Newspaper headlines, while sensational, can easily turn misleading or even add to the confusion; it is far better now to err on the side of caution. Never before have the people been needed to pay more attention only to qualified scientists anywhere on the planet but especially in India.

Celebrities for all their laudable efforts in disseminating information may inadvertently add to the chaos. We cannot afford an Idris Elba staring into the camera in all seriousness to announce that he has COVID-19 with his wife, who had first tested negative, standing next to him. It does not bode well for Elba to advertise a lack of awareness that his wife or anyone else should have been in a different room. Silence was never more golden.

Deepak Natarajan is a cardiologist based in New Delhi.