IF scientists are right, face masks may move from masquerades to mainstream. According to a Queensland University of Technology post yesterday, 239 scientists from around the world, led by its air quality and health expert Professor Lidia Morawska, say overwhelming research findings point to airborne transmission of Covid-19.
In a letter titled "It is Time to Address Airborne Transmission of Covid-19" to be published this week in the Clinical Infectious Diseases journal, they call on the international health authorities "to recognise and mitigate airborne transmission of Covid-19". It is no ordinary letter.
It's a plea, and there is a reason why the letter comes dressed as such. The World Health Organisation (WHO) is heavy on droplets and close contacts and less so on aerosol transmission.
Little wonder, its health protocols call on us to keep our social distance only up to 1.5 to 2m, while airborne transmission can take the coronavirus much further. And it lingers much longer in the air than WHO is acknowledging.
One reason why WHO is so much into droplets is offered by Apoorva Mandavilli of The New York Times, who spoke to WHO and some of the 239 scientists.
WHO may have been too reliant on samples taken from hospital rooms, where good airflow would have diluted the viral level, Linsey Marr, an expert in airborne transmission of viruses at Virginia Tech, told the American newspaper.
Just because we can't grow the virus in labs, doesn't mean it is not there. She has a point. Sometimes, we do get what we don't see. Besides, talking and coughing do generate aerosols, as common knowledge will suggest. And according to Marr, the scientific community has known this since 1946. Perhaps the medical community that crowds WHO may see things differently. Two scientists, like two lawyers, often disagree.
Be that as it may, it is best to adopt what is often termed the precautionary principle or otherwise known as giving the aerosol transmission the benefit of the doubt.
This doesn't mean discarding the current health protocols. What it means though is we have to do more, now that fresh evidence is emerging that the coronavirus is mutating.
Much of this work will be on how to make ventilation efficient and effective indoors. Those who are sceptical may want to give Professor Morawska another hearing.
Here is why. At typical indoor velocities, she says, a 5-micron droplet will travel tens of metres, much greater than the scale of an average room while settling from a height of 1.5m above the floor. Ignore her at our peril.
How do we mitigate airborne transmission? The scientists recommend we start indoors, where poor ventilation is a major contributor to the viral spread. Think workplace, schools, malls, restaurants, care homes and everything that has a roof and walls.
Think, too, of exhausts for buildings, high efficiency air filtration and germicidal ultraviolet lights.
Sure, such things cost money, but it will be penny wise pound foolish to pit the precautionary principle against the opportunity cost as WHO seems to be doing.
Perhaps it is thinking of one size for all — the poor, the rich and every country in between. And about the face mask, it may now be necessary to wear it, even when indoors. For this is the way we may live for now.