The spread of COVID-19:
The World Health Organization (WHO) published on the 29th of March, 2020, that respiratory infections – including the transmission of SARS-CoV-2 – are transmitted via droplets of differing sizes. By conducting an analysis of over seventy-five thousand cases that were reported in China, it was conclusively proven that Coronavirus spreads from person to person via bodily fluid droplets, not air.
A report published on the 9th of July by the same organization has also stated that airborne transmission of COVID-19 cannot be completely ruled out. Special cases where the probability of airborne transmission include medical procedures and crowded, indoor spaces. They have stated that “more studies are urgently needed” when it comes to studying the airborne transmission of the virus, now that transmission by contact and respiratory droplets have been concluded to the best of their understanding.
Why is this being considered?
Donald Milton, a professor of environmental health at the University of Maryland, helped lead a group of 239 scientists in writing an open letter. In this, they had appealed for better recognition of how potent the airborne transmission of SARS-CoV-2 is. Professor Milton has reported that the agencies “seem to be afraid to talk about the airborne nature of the virus”.
According to him, the perfect situation for the spread of coronavirus would be a noisy, crowded bar, where people are clustered together and every door and window is shut, leading to re-circulation of air within the environment, containing and spreading the disease. He had also stated that “they do not want to talk about airborne transmission, because that is going to make people afraid”. Worry and mass hysteria should also be taken into consideration, wherein the acknowledgement of the airborne trait of the virus could lead to people stopping other habits that are currently slowing down transmission, such as washing hands, distancing themselves, and cleaning surfaces.
According to him, studies conducted by various scientists have exhibited the release of various viruses while exhaling, talking, and coughing – activities that lead to micro-droplets large enough to contain microbes, and small enough to linger about in the air for long periods of time, causing a risk of exposure beyond two meters from the point source.
“At typical indoor air velocities, a five-nanometer droplet can travel tens of meters while staying below two meters from the floor of the room”, he stated. While studies show droplet size is a factor in the transmission effectiveness of SARS-CoV-2, its importance is yet to be understood. According to his statements, he is concerned about the transmission of the disease in places where people congregate, such as churches and college campuses.
The WHO report:
Airborne transmission of the virus can occur in health care settings where specific medical procedures (such as aerosol generation) can produce miniscule droplets termed aerosols. Outbreak reports that are related to crowded indoor spaces have suggested that there are possibilities where the virus can be transmitted via aerosols – this, in combination with droplet transmission, can lead to an incredibly fast spread of the virus.
Current evidence still suggests that the primary mode of transmission of SARS-CoV-2 occurs by direct, indirect, or close contact with infected people, via infected bodily secretions or respiratory droplets expelled when the infected person exhales, talks, or sneezes. Such droplets can also land on objects near the infected, which can lead to another healthy person getting infected when in contact with the object.
With reports of transmission of COVID-19 in indoor spaces increasing by the day, the WHO have stated that aerosol transmission within crowded spaces cannot be ruled out. Supported by inadequate ventilation and infected people spending long periods of time among crowds, more studies are currently being conducted to investigate such instances to assess their significance for the transmission of the disease.
Additional reports from experts:
Brittany Kmush, assistant professor specializing in public health and infectious disease at the Syracuse University in New York, has commented that there is a difference between particles released from coughing and sneezing and aerosolized particles. While not involved in the WHO report, she stated that droplet transmission is essentially airborne, with the expulsion travelling via air at high speeds and causing an infection a distance away, not requiring direct contact.
With tiny particles that can linger in the air for longer periods of time, professor Kmush believes that COVID-19 can be transmitted via this method, utilizing aerosolized particles. This does not, in any way, cancels out the need for masks, self-quarantine, or social distancing, she added.
During a media briefing in Geneva, the technical lead for infection prevention and control for the WHO, Dr. Benedetta Alleganzi, reported that the agency had discussed in collaboration with scientists from the Milton group who had signed the appeal about the organization not being forthcoming about the airborne trait of SARS-CoV-2. With emerging evidence in the field, Alleganzi stated that the organization is open to all evidence and its implications regarding the modes of transmission, and the precautions that are to be taken should newer evidence be brought to light.
Another executive of the WHO, Maria van Kerkhove, the organization’s technical lead for coronavirus response and head of emerging diseases and zoonoses unit, talked about the discussions being held on the possibility of airborne and aerosol transmissions of COVID-19. As a respiratory pathology, it is important to understand what fits into the guidance that the organization has – a “comprehensive package of interventions is required to be able to stop transmission”.
Such a package includes not just physical and social distancing measures, but also effective utilization of respiratory masks of all kinds when in appropriate settings, especially for health care workers.
Paul Hunter, professor of medicine at the University of East Anglia, UK, has written that the WHO report does not change the stance of global health officials and experts about the airborne transmission of COVID-19. This statement has been distributed by Science Media Centre, a UK-based publisher, since the 10th of July, 2020. Professor Hunter also stated that the frenzied interest in this possibility has done nothing to change the position of the WHO.
Staying safe during this pandemic:
This new report has brought to light some devastating possibilities of the virus, should healthy people be caught up in crowded spaces with infected people. But this does not change the safety measures we have been taking as a collective all this time – rather, this report is now a disclaimer on the safety measures we need to take in the near future. In Professor Milton’s appeal letter, practical advice about staying safe from SARS-CoV-2 has been included for our sake. With these new possibilities, the new safety measures will now have to include sufficient and effective ventilation in public buildings, work place environments, schools, hospitals, and retirement homes.
Ventilated spaces must now be supplemented with airborne infection control methods, such as local exhausts, highly-efficient air filters, and germicidal ultraviolet lights placed far away to mitigate skin and eye damage by exposure. Overcrowding, as previously followed, must be avoided at all costs; safe physical distance maintenance, while not the ultimate transmission prohibition method, can lead to lower chances of people getting infected. This must be followed with strict measures in public transport and buildings particularly.
These steps are easily implementable, and are generally cheap as well. Some, like maintenance of distance, requires not money but a strict rule-and-punishment system – while it may sound harsh, it is the only way to contain the spread of the virus and end the pandemic as we know it.