SARS-CoV-2 (the novel coronavirus) IS AIRBORNE! Here are 10 pieces of evidence

Until recently, the novel coronavirus (SARS-CoV-2) was thought to spread through respiratory droplets released from a person’s mouth and nose. However, according to the findings and conclusions of a review funded by WHO (the World Health Organization) and released as a preprint in March 2021, coronavirus is airborne, and this mode of spread may even be more important than droplet transmission.

The concepts of aerosol, airbone (airborne) and droplet

Aerosol

An aerosol is a particle suspended in the air. Aerosol is an umbrella term for any solid or liquid particle so small and light that it can remain suspended and float in the air. Smoke and dust are examples. Some viruses can become aerosolized, allowing airborne transmission.

WHO describes aerosol transmission, also known as airborne transmission, as "very small droplets that can remain suspended in the air for longer periods."

Airbone

According to WHO, airborne transmission involves a virus-containing droplet small enough to float in the air, and occurs when someone else inhales the infectious particle.

The World Health Organization said there is growing evidence that airborne transmission of COVID-19 may be possible because of COVID-19 outbreaks reported in certain indoor settings, such as restaurants, nightclubs, places of worship or workplaces, especially poorly ventilated spaces. People in these settings may be shouting, talking or singing.

Note: Aerosol and airbone spread are often used to describe the same situation, namely airborne transmission.

Droplets

Droplets are large mucus or saliva particles that are heavier than air and fall toward the ground as soon as they are expelled. Droplet transmission typically occurs when a virus-containing droplet comes into contact with another person’s eyes, nose or mouth. An example might be a person speaking loudly whose droplets come into contact with your face.

According to WHO, the available evidence indicates that COVID-19 spreads primarily through close contact, from person to person, as droplets are released from the mouth or nose when an infected person coughs, sneezes, talks or sings. For example, people in close contact with an infected person may become infected when these infectious droplets enter their mouth, nose or eyes.

10 pieces of evidence that coronavirus is transmitted through the air

If a disease-causing virus spreads through large respiratory droplets that fall quickly, the main control measures include reducing direct contact, preventing physical contact, maintaining social distance, wearing masks and cleaning surfaces to which respiratory droplets may adhere. Since the gravity required for droplets to fall and spread does not depend on whether the setting is indoors or outdoors, no distinction should be made when taking such measures. However, if the infectious virus is mainly airborne, another person who inhales the airborne particles released when an infected person breathes out, talks, shouts, sings, sneezes or coughs may potentially become infected.

1. Factors that could also be called superspreaders may be the main forces driving the spread of SARS-CoV-2. Detailed analyses of human behavior and types of interaction, room sizes in shared living spaces, ventilation and other factors, as well as mass events such as concerts, have shown patterns consistent with airborne spread of SARS-CoV-2 that cannot be adequately explained by droplets or fomites (inanimate objects carrying microbial infections). Frequent reports of such events strongly suggest that airborne transmission is important.
2. The spread of SARS-CoV-2 from people who are not coughing or sneezing, whether symptomatic or asymptomatic may account for at least one-third, and perhaps as much as 59%, of all transmission globally. This is an important point supporting the predominantly airborne worldwide spread of SARS-CoV-2.
3. SARS-CoV-2 spreads more readily indoors than outdoors, and transmission in enclosed spaces can be significantly reduced by ventilation. Observations in both settings again support airborne transmission.
4. Healthcare facilities have documented that nosocomial infections (hospital-acquired infections) can occur even when personal protective equipment (PPE) designed to protect against droplets, but not exposure to airborne particles, is used.
5. Viable SARS-CoV-2 has been detected in the air. In laboratory experiments, SAR-CoV-2 remained infectious in the air for up to 3 hours, with a half-life of 1-1.5 hours. Viable SARS-CoV-2 virus was detected in air samples from rooms with COVID-19 patients and in an air sample from an infected person’s car. Sampling airborne virus is technically difficult because of viral capture challenges, including viral damage, loss of viability and reaerosolization during collection. It is therefore unsurprising that other studies failed to capture SARS-CoV-2 in the air. For example, airborne measles and tuberculosis have never been recovered from room air.
6. SARS-CoV-2 has been identified in air filters and ducts in hospitals with COVID-19 patients, places that can be reached only by airborne particles.
7. Studies connecting the cages of infected and uninfected animals through an air duct show that transmission of SARS-CoV-2 by airborne particles can be adequately demonstrated.
8. No studies provide strong or consistent evidence refuting the hypothesis of airborne SARS-CoV-2 transmission. Some people breathe the same air as infected individuals without contracting SARS-CoV-2, but this can be explained by many factors, including differences of several orders of magnitude in viral shedding among infectious individuals and differences in environmental conditions, especially ventilation. Individual and environmental differences mean that a small proportion of primary cases, particularly individuals shedding high levels of virus in enclosed, crowded, poorly ventilated settings, account for most secondary infections. This is supported by high-quality contact-tracing data from various countries.
9. There is limited evidence supporting other dominant routes of spread, namely respiratory droplets or fomites. The ease of transmission between people in close contact has been cited as evidence that SARS-CoV-2 spreads through respiratory droplets. Mistaken assumptions that close-range transmission indicates large respiratory droplets or fomites were also used for years to deny the airborne transmission of tuberculosis and measles. The notion that respiratory droplets contain more virus because they are larger than airborne particles is sometimes debated. However, in diseases in which pathogen concentrations have been measured by particle size, smaller airborne particles showed higher pathogen concentrations than droplets when both were measured.
10. Long-distance spread of SARS-CoV-2 between people staying in neighboring rooms in quarantine hotels has not been documented so far. However, long-distance transmission can be demonstrated only in the complete absence of community spread.

In conclusion, the team argues that it is a scientific error to use the lack of direct evidence of SARS-CoV-2 in some air samples to cast doubt on airborne spread while disregarding the quality and strength of the overall evidence base. There is consistent, strong evidence of airborne SARS-CoV-2 transmission. For this reason, although other routes may contribute, airborne spread is believed to be more dominant. The public health community should act with this in mind, without further delay.

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