A new study in The Lancet has shown that the novel coronavirus manages to stay in faeces of patients for five weeks even after respiratory samples test negative, indicating that the decision to discharge patients should not be based just on nasal swabs.
India has so far recorded 23 recoveries and the discharge of coronavirus patients.
The study, titled ‘Prolonged presence of SARS-CoV-2 viral RNA in faecal samples’, analysed respiratory and faecal matter of 74 COVID-19 patients from January 16 till March 15 at Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China. In 55 percent cases (41 of 74 patients), respiratory samples, meaning throat swab, tested positive for coronavirus for 16.7 days and faecal matter tested positive for the virus for 27.9 days after first onset of symptoms.
In at least one patient, faecal samples for the virus came positive for 33 days even after the virus was not detected in respiratory samples, and in another patient the virus was present for 47 days after first symptoms of infection surfaced.
“And this study just talks about respiratory and faecal samples. What we also need is an understanding of how long the virus survives in vaginal swabs, saliva, semen, tears,” said Dr Om Srivastava, infectious disease expert in Jaslok hospital, who is treating a 37-year-old COVID-19 patient in critical condition in Mumbai. Srivastava said Zika virus manages to remain in semen for nine months, posing a risk of transmission. “It is possible further studies will suggest something similar for SARS-CoV-2. It is possible people discharged continue viral shedding,” he added.
Currently, a COVID-19 patient is discharged after two nasopharyngeal swabs test negative for the virus in a gap of 24 hours. The study points towards a need to have more parameters before discharging patients. “Here, we observed that for over half of patients, their faecal samples remained positive for SARS-CoV-2 RNA for a mean of 11.2 days after respiratory tract samples became negative for SARS-CoV-2 RNA, implying that the virus is actively replicating in the patient’s gastrointestinal tract and that faecal-oral transmission could occur after viral clearance in the respiratory tract,” the study said.
The study further said that there is a possibility of viral shedding for nearly five weeks from faeces. The virus could remain in environment for days, and transmit through faecal-oral transmission mode.
Dr Jayanthi Shastri, heading the Kasturba laboratory which is testing over 100 samples a day, said everyday blood, urine and stool sample of a positive patient is sent to the National Institute of Virology for analysis. “NIV is studying day-by-day a patient’s viral shedding to assess how long virus stays in body,” Shastri said.
India is admitting confirmed cases for a minimum of 14 days in isolation ward. Based on latest findings, the definition of recovery period of 14 days also changes. A recovered discharged person may pose transmission risk to others.
Dr Daksha Shah, deputy executive health officer in BMC, said, “Currently, we follow central guidelines and discharge patients if two respiratory tests come negative. Until a new directive comes, patients will remain for at least 14 days in isolation ward.”
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