Much has changed since coronavirus, or COVID-19, was first detected in late December 2019, including guidelines on public health. In the most recent debate, more than 200 experts have banded together to claim another big development — coronavirus is allegedly airborne too and they want the World Health Organisation (WHO) to recognise it.
It’s not the first there’s been a push by the expert community to change the WHO’s definitions and guidelines on the contagious virus that has infected more than 11 million and killed more than half a million.
At first, it wasn’t known whether human-to-human transmission was possible and it was eventually confirmed once numbers outside of Wuhan quickly rose. The WHO also argued against closing international borders but it was soon realised it was an unfortunate but necessary measure to stop further spread.
Now more than 200 experts have banded together to claim another big change in the world’s understanding of the virus — COVID-19 is allegedly airborne and they want WHO to recognise it.
Who says coronavirus is airborne?
In late March 2020, the WHO released an update on coronavirus’ modes of transmissions, highlighting respiratory droplets as the primary means of transmission. Droplets are spread most commonly through coughing or sneezing but can also be passed on if people come into contact with an infected surface. It also noted airborne and faecal transmission were possible but there had been no reported cases at the time to verify these findings.
As reported cases continue to rise past the 11 million mark, so too does our understanding of the virus. It happened with anosmia — loss of smell — which was added by the WHO as a ‘less common’ symptom after experts said the evidence was mounting.
Now, a group of 239 experts believe the virus is also airborne and they want the WHO to change its definition so countries can better respond, according to the New York Times.
The group is made up of health experts around the world, many of whom have consulted with the organisation since the pandemic started.
“I do get frustrated about the issues of airflow and sizing of particles, absolutely,” Professor Mary-Louise McLaws, an epidemiologist and WHO committee member at UNSW, told the New York Times.
“If we started revisiting airflow, we would have to be prepared to change a lot of what we do … I think it’s a good idea, a very good idea, but it will cause an enormous shudder through the infection control society.”
Airborne transmission differs from droplets in that the disease-causing microbes can exist after the droplet has evaporated. This means they can last longer and travel further than the general one-metre rule.
Other well-known airborne diseases include tuberculosis, chickenpox and the highly contagious disease, measles.
The group of experts pointed to evidence that showed the virus was able to spread more efficiently in poorly ventilated and crowded indoor spaces, suggesting it wasn’t just being transmitted via droplets. It believes a change in the definition is needed so better methods of limiting spread can be tested.
Why doesn’t the WHO agree?
While the evidence is growing, the WHO has said it needs more hard facts given the reports are not definitive. It has since acknowledged there is growing evidence that airborne transmission could be more prominent than previously thought.
In news briefing on 7 July, the lead of the WHO’s committee on infection prevention and control, Dr Benedetta Allegranzi, admitted the organisation would look into the growing evidence as presented by the world’s experts.
“We acknowledge that there is emerging evidence in this field, as in all other fields,” Dr Allegranzi said at the briefing in Geneva.
“Therefore, we believe that we have to be open to this evidence and understand its implications regarding the modes of transmission and also regarding the precautions that need to be taken.” Dr Allegranzi said.
Its guidance update at the end of June said that droplet transmission was the primary mode, conceding it could become airborne during certain medical procedures.
Still, it said while there was evidence airborne particles of coronavirus were found in patient rooms where these medical procedures had not been undertaken, the virus could not be extracted from them.
“None of these studies have been able to culture the virus from these air particles, a step that is critical to determining the infectiousness of viral particles,” the guidance read.
But the group of experts said this didn’t mean those airborne particles weren’t capable of transmitting the disease. Airborne transmission expert Dr Linsey Marr told the New York Times samples taken from those infected patients were likely to be diluted due to a hospital generally having good airflow.
That could mean the airborne particles might still be infectious but perhaps not to the level of very contagious diseases like measles.
Instead, the scientists are pushing WHO to assume the worst and recommend methods — even if not yet definitive — to stop the virus from spreading. Given worldwide cases are nearing 12 million and there’s no sign of slowing at its six-month mark, it might be a better time than ever.
Update (8/7/2020): This article’s headline and body was updated to include WHO’s acknowledgement of the evidence supporting airborne transmission.