Airborne transmission contributing to increasing infection rates of SARS-CoV-2.

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Whenever you breathe, speak, sing, laugh, cough or sneeze, droplets are produced and spread throughout your immediate environment. If you’re infected with SARS-COV-2, then these droplets are disbursed around you, becoming a source of infection for others. Generally, there are 3 principal ways transmission occurs:

  1. Inhalation of very small droplets and aerosol particles,
  2. Deposition of virus carried particles onto exposed mucous membranes – such as being coughed on.
  3. Through touching surfaces that are infected with mucous membranes.

To mitigate the risk of contracting the virus, various safety measures are implemented, such as wearing face coverings and masks, practicing social distancing, cleaning and disinfecting surfaces. However, as we continue to learn about COVID through research and real-life exposure, we now have a greater understanding of how the virus is spread and what sources are cause for most concern; with airborne transmission emerging as a serious contributor to the increasing infection rates being experienced.

When large droplets are produced, these are heavy which causes them to fall to the ground quickly. This means surfaces become sources of transmission and people within close proximity are at risk of infection. Because of this, social distancing and disinfecting are effective measures to limit the transmission risk. However, with aerosols, which are much finer and lighter, they can stay suspended in the air, traveling far further than just 6 ft, with research supporting the possibility of up to 27ft travel while remaining infectious for many hours. When it comes to enclosed spaces, the perfect conditions for the virus to survive and remain active can be created, with no sunlight, consistent temperature, and movement from people that can move the airborne particles around. Because of this, people may think they are safe but are in fact unknowingly coming into contact with the virus, even though they have had no direct contact with an infected person. In these instances, the face coverings and masks being worn may not provide complete protection as these are not always fitted correctly, leaving gaps that the virus can be respired through.

Transmission in hospitals

With the disproportionate infection rates in hospitals, Infectious Clinicians, Aerosol Scientists and Engineers have worked together to gain a better understanding of airborne transmissions within healthcare. From this, they have established that ventilation in these spaces to be a significant issue, with HVAC systems primarily designed for comfort and energy efficiency and not filtering infectious airborne particulates. The direction of airflow can directly affect staff and patient safety as airborne aerosols could be directed to areas, where infected patients are not even permitted. From their findings, these specialists recommend that patients with COVID are shifted to negative pressure rooms as this is more likely to limit airborne transmission as the droplets generated by these patients are contained within this space, preventing the virus from spreading throughout the hospital.

Although retrofitting ventilation systems and building additional infrastructure that can house patients with highly infectious diseases is a desirable course of action, it is costly and would take a considerable amount of time to complete. With case numbers continuing to rise causing hospitals to become overrun, this means other avenues need to be explored to protect both staff and patients immediately. The easiest, and one of the most effective ways to address these issues in healthcare settings is by using PPE, and in particular powered air purifying respirators (PAPRs). Throughout the pandemic, healthcare workers have been contracting the virus, which not only puts the staff at risk but adds further stress to the healthcare system by further stretching staffing resources. Healthcare facilities that have employed the use of PAPRs have seen staff transmission rates drop completely, with some reporting 0 cases since their introduction. These systems offer a higher level of filtration efficiency, compared to traditional tight-fitting respirators, while providing additional protection covering the entire face. This allows the healthcare workers to provide their patients with the care they need, without the fear and risk of infection.

Although we are a long way off defeating the pandemic, we continue to learn every day, and through this, we’re able to solve the problems that we face with technology that is already here, ready and available.

Works Cited

Buising et al. (2021, August 16). We studied how to reduce airborne COVID spread in hospitals. Here’s what we learnt. Retrieved from The Conversation:

CDC. (2021, May 7). Scientific Brief: SARS-CoV-2 Transmission. Retrieved from CDC:

Coleman et al. (2021, August 6). Viral Load of SARS-CoV-2 in Respiratory Aerosols Emitted by COVID-19 Patients while Breathing, Talking, and Singing. Retrieved from Oxford Academic:

European Comission. (2021, June 31). COVID-19: How a better understanding of airborne transmission is the key to break the chain of infection. Retrieved from European Comission:

Klompas et al. (2020, July 2020). Airborne Transmission of SARS-CoV-2. Retrieved from JAMA Network:

Morawska, L. (2021, July 26). Australia must get serious about airborne infection transmission. Here’s what we need to do. Retrieved from The Conversation:

Saey, T. H. (2021, August 18). New studies hint that the coronavirus may be evolving to become more airborne. Retrieved from Science News:

Singapore, N. U. (2021, August 11). Fine aerosols emitted during talking and singing may play a crucial role in COVID-19 transmission: Singapore study. Retrieved from Science Daily: