Can you smell what your mate has had for lunch? If the answer is yes, you’re standing too close or the room isn’t ventilated enough, according to scientists encouraging people to consider the ‘garlic-breath distance’.
In a new study, scientists emphasise how “close airborne transmission of the virus... is considered to be the primary route for its circulation”.
While early efforts to stop the spread of Covid-19 focussed on hand washing and contaminated surfaces, the virus is actually most likely to transmit between people at close range through inhalation, they said.
Lead author Dr Julian Tang, associate professor of respiratory sciences at the University of Leicester, suggested that the ‘garlic breath test’ may be useful way to see if you’re standing close enough to someone to catch Covid.
“The way this virus transmits is really through conversational distance, within one metre,” he told Sky News. “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.”
In the study, published in the British Medical Journal (BMJ), researchers 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... The transmission of Sars-CoV-2 after touching surfaces is now considered to be relatively minimal.”
Dr Chaand Nagpaul, chairman of council at the BMA, said the BMJ study emphasised how “crucial” clean airflow is. “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 through-flow in buildings and on public transport,” he added.
Dr Nagpaul called for investment in hospitals, clinics and GP surgeries to ensure they are properly ventilated, as well as specifications on ventilation in workplaces and the hospitality sector. “A failure to ensure adequate levels of ventilation in indoor areas runs the serious risk of a rebound increase in Covid-19 infections,” he said.
“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.”