People should use the “garlic-breath distance” to decipher whether they are close enough to another person for coronavirus transmission to occur, an expert has said.
Dr Julian Tang, a consultant virologist at the Leicester Royal Infirmary and the author of a new study published in the British Medical Journal (BMJ), stressed that governments and health leaders should “focus their efforts on airborne transmission”.
Asked if focusing on hand-washing and sanitising was wrong, he said the emphasis was not correct. Speaking on Sky News, he said: “So the message ‘hands, face, space’, we think should be really ‘space, space, hands’. The way this virus transmits is really through conversational distance, within one metre.
“When you’re talking to a friend or sharing the same air as you’re listening to your friend talking, we call it the garlic-breath distance. So if you can smell your friend’s lunch you’re inhaling some of that air as well as any virus that’s inhaled with it.
“And this is why we say that masking is fine, social distancing is fine, but the indoor airborne environment needs to be improved and that can be done with ventilation.”
The British Medical Association (BMA) said the government had clearly conveyed the “hands, face, space” message but more needed to be done to promote the importance of fresh air. Pubs, bars and restaurants, workplaces and other public settings should be given ventilation guidance as they prepare to bring customers indoors again, the BMA said.
An article in the BMJ emphasised the importance of aerosol transmission of the virus. The authors, from the University of Leicester, the University of Hong Kong, Edinburgh Napier University and Virginia Tech in the US, said the “tiniest suspended particles can remain airborne for hours”.
They added: “People are much more likely to become infected in a room with windows that can’t be opened or lacking any ventilation system.”
The article went on: “It is now clear that Sars-CoV-2 transmits mostly between people at close range through inhalation. This does not mean that transmission through contact with surfaces or that the longer-range airborne route does not occur, but these routes of transmission are less important during brief everyday interactions over the usual 1-metre conversational distance.
“The transmission of Sars-CoV-2 after touching surfaces is now considered to be relatively minimal.”
Dr Chaand Nagpaul, the chair of the council of the BMA, said the article emphasised how crucial clean airflow was. “There has been much discussion by the government and in the media about ‘hands, face and space’ but much less about the critical importance of fresh air and throughflow in buildings and on public transport.
“As restrictions are eased, and there is greater mixing between people in enclosed spaces, it is vital that measures are taken to ensure adequate ventilation.
“A failure to ensure adequate levels of ventilation in indoor areas runs the serious risk of a rebound increase in Covid-19 infections. Crucially, patients and the public need to know they are as safe as they can be and at low risk of becoming infected with Covid-19 when they return to the office, go shopping or go into leisure settings.”