Coronavirus genetic material detected in air, unclear if it causes disease: Study

Scientists have revealed evidence for the presence of the genetic material of the novel coronavirus in the air, but say that it is unclear if these suspended viral particles are infectious.

By monitoring the environment around two hospitals and some public areas in Wuhan, China, researchers, including those from Wuhan University in China, revealed hotspots for airborne novel coronavirus RNA.

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However, whether this material has the potential to infect was not assessed in the study, published in the journal Nature.

Although the sample size of the study was small, with fewer than 40 samples from 31 locations, the findings, according to the researchers, support notions that careful sanitisation, good ventilation, and avoidance of crowds can reduce the risk of airborne virus exposure.

Until now, reported modes of SARS-CoV-2 RNA transmission to humans include close contact with infected individuals, contact with contaminated surfaces, or inhalation of droplets released from the respiratory system of people with the virus, the scientists said.

Whether there is further potential for SARS-CoV-2 to spread through the air has been less clear, they added.

Ke Lan and his team set up aerosol traps in and around two government-designated hospitals for the treatment of patients with COVID-19 during February and March 2020.

According to the study, these sites included a grade-A tertiary hospital for patients with severe illness and a field hospital for patients with mild symptoms.

The researchers said the concentration in ventilated patient wards was generally very low, attributing this to effective isolation and high air exchange.

However, patient toilets, which were not ventilated, had elevated concentrations of airborne viral RNA, they said.

The study noted that viral RNA was especially concentrated in areas used by medical staff to take off protective equipment, suggesting that virus-laden aerosols can become resuspended in the air when this equipment is removed.

But after increasing the rigour and frequency of sanitisation efforts, no detectable evidence of airborne SARS-CoV-2 RNA was found in medical staff areas, the scientists said.

In public areas outside the hospitals such as residential buildings and supermarkets, the study said the concentrations of SARS-CoV-2 RNA were generally low.

However, two areas that were subject to large crowds passing through, including an outdoor space near to one of the hospitals, had elevated concentrations of SARS-CoV-2 RNA, the scientists added.

They suggested that individuals infected with SARS-CoV-2 within these crowded areas may have contributed to the viral aerosols.

The researchers cautioned that the study does not reveal whether the SARS-CoV-2 RNA has the potential to be infectious.

They said restricted access to the hospitals during the peak outbreak limited the number of samples that could be taken.

Nonetheless, the scientists noted that the findings support the use of thorough sterilisation of potential hotspots for virus-laden aerosols, well-ventilated hospitals, and avoidance of crowds to reduce the risk of infection.