Since the pandemic began researchers from all around the world arguing the existence form of the novel coronavirus. And the burning debate question is how Covid-19 spreads - many contradictory aspects found in this particular topic, however, by collecting some sort of information from different sources make that read possible which include some references, WHO reports, examining a real case, and how can we prevent this form of transmission.
What does airborne transmission mean?
Scientists distinguished between respiratory infectious diseases categorized as "airborne" - which spread by aerosols suspended in the air.
Basically, aerosols are tiny liquid particles followed by the respiratory tract that is generated when someone exhales, coughs, sneezes, and talks. They are dispersed in the air and contain live viruses, such examples are measles and chickenpox. Both diseases are highly infectious classed as airborne because they are spread by aerosols.
On the contrary, illness such as influenza is thought to spread through larger respiratory droplets. These do not float easily as aerosols and are likely to fall to the ground within 1-2m of the source.
Is airborne disease is more transmissible? understand how
Just take an example, infectious person A produced an aerosol in a small, poorly ventilated room over time. If person A departs the room, it might be left aerosol behind. If person B arrives in the room and spends some time there, they could be infected by breathing in the contaminated air.
According to Julian Tang, consultant virologist at the Leicester Royal Infirmary. "Droplets hit the ground, they're not inhaled, Everything else is an aerosol when inhaled, regardless of size."
Some of the officials from WHO states that aerosols are liquid particles consist size of five microns or less in diameter. However, larger particles of moisture can also become suspended for a time in the air, depending on conditions such as temperature, humidity, and air. This means it can be difficult to make that perception that a virus has zero opportunity for airborne transmission.
Is Covid-19 airborne?
The report published in August 2020 found that a single infected in the early stage could emit millions of SARS-CoV-2 particles per hour through breathing alone. Some evidence also convinced that aerosols emitted when someone speaking at a normal volume or merely breathing.
Meanwhile, scientists still aren't sure how long viable, infectious virus particles can linger in the air. Analysis might detect the virus's RNA but generally find no whole, infectious virus particles. This doesn't mean viable particles were not present - it might simply be that the sampling technique was unable to retrieve them intact.
Despite these unknowns, several case studies suggest airborne transmission, which spread to distances beyond two meters from the infectious person.
Examining a case, a restaurant in Guangzhou, China, 10 people dined on January 2020, shortly before testing positive for Covid-19. Three families were seated around three separate tables, but near to each other. One family had traveled from Wuhan. There was no physical interaction that happened. However, a study of the restaurant's ventilation systems, security camera footage, and the case histories of those present concluded that infectious particles carried in the air were likely responsible for the spread of the virus.
The team of researchers argued in the Lancet10 that aerosols were likely to be the dominant route for the transmission of SARS-CoV-2. With the fact that transmission is much higher indoors than outdoors; and that asymptomatic or pre-symptomatic transmission is thought to have caused a significant number of infections worldwide.
When someone is not coughing, they may produce fewer droplets but still emit many aerosols.
WHO stance over Covid-19 airborne transmission:
WHO published a report in the context of Covid-19 in March 2021, states 'The virus can spread from an infected person's mouth or nose in small liquid particles when the person coughs, sneezes, sings, breathes heavily, or talks. These liquid particles are of different sizes, ranging from larger 'respiratory droplets' to smaller aerosols.
"Aerosol transmission can occur in specific situations in which procedures that generate aerosols are performed."
WHO was initially adamant that airborne transmission of SARS-CoV-2 was not possible, however, since March 2020, WHO has gradually changed its stance. The official advice reads, 'Airborne transmission of SARS-CoV-2 can occur during medical procedures that generate aerosols.
The agency further added that the term "airborne" has a specific medical meaning that applies to diseases such as measles, which transmits predominantly through the air and across long distances. For Covid-19, WHO added, "the virus predominately spreads through close, or direct, contact, or possibly contaminated surfaces. That is why it is not called an airborne virus,"
How can we prevent airborne transmission?
No rocket science behind it, just opting for precautionary measures including ventilation and avoiding enclosed space. Japan puts emphasis on avoiding the "3C's": crowded places, close contact, close conversations. Some researchers estimated that the risk of infection could be three times higher in a poorly ventilated room as opposed to one that underwent 10 air changes per hour.
This may be one of the reasons why some governments are reluctant to officially declare SARS-CoV-2 "airborne", says Catherine Noakes, professor of environmental engineering for buildings at the University of Leeds. "If you think something transmits on surfaces, it's easy to do a precautionary approach and tell everybody to wash their hands. But if we say it's in the air, that means some quite major capital investments to buildings and technologies, she says.
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