On Thursday, July 9, the World Health Organization (WHO) officially accepted that the coronavirus could be transmitted through airborne droplets in the air indoors. Their announcement was a reversal for the United Nations agency.
In a scientific briefing, the organization said that people who spend time in congested places with poor ventilation are at risk of being infected with COVID-19. This is more likely since droplets circulate through the air in indoor settings, the agency said.
The review came after more than 200 experts from around the world gathered to push the organization into updating its description of the virus' route of transmission.
WHO Concedes to Scientists' Plea: Coronavirus is Airborne
The WHO now recognizes that viral transmissions through aerosols, or tiny air droplets, might have been responsible for reported outbreaks of COVID-19 in some closed settings. Some locations of the cases include places of worship, night clubs, bars, restaurants, workplaces, and other environments where people may be talking, singing, or shouting.
The WHO now updates its guidelines and advises people to avoid crowded places, close-contact ambiances, and enclosed spaces with poor ventilation.
The organization still primarily focuses on the coronavirus' transmission through large droplets expelled through sneezing or coughing. However, it now also recognizes the possibility of airborne transmission.
The agency writes that respiratory droplet transmission can happen when a person with respiratory symptoms expels droplets through coughing, sneezing, or talking to a person about a meter away.
In these circumstances, the virus can reach the other person's mouth, nose, or eyes, making the transmission of the SARS-CoV-2 virus possible.
The WHO previously directed that airborne transmission is only common when people, particularly health care workers, were involved in medical practices that produce aerosols.
However, mounting evidence has accumulated, suggesting that the virus can stay suspended in the air for hours and infect a person upon inhalation.
Airborne Transmission of COVID-19
The WHO defines airborne transmission as the spread of an infectious agent caused by disseminating droplet nuclei or aerosols that remain infectious when suspended in air over long periods and distances.
The agency claims that the science behind exhaled air and flow physics suggests that respiratory droplets can create microscopic aerosols by evaporation. Furthermore, normal breathing could also take in the exhaled aerosols.
From these theories, they claim that a susceptible person could inhale the potentially harmful aerosols and become infected with the virus it contains.
However, the proportion of exhaled respiratory droplets that evaporate to create aerosols, and the infectious dose of viable SARS-CoV-2 needed to cause an infection in another individual are yet to be known.
Modes of Transmission of SARS-CoV-2
The WHO claims that the coronavirus can be transmitted through various modes, including contact and droplet, airborne, fomite, and through human biological samples.
Although the main focus is on large droplets, the agency recognizes that bodily fluids and humanly products of excretion could also carry the harmful virus. Additionally, fomites or contaminated surfaces also pose a risk for transmission.
To prevent the further spread of the virus, the WHO advises people to be knowledgeable about its routes of transmission to break the chain and to practice preventive measures.
Some of their recommended practices are wearing masks, physical distancing, respiratory etiquette, proper hand hygiene, and refraining from visiting crowded indoor settings.
