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Researchers' virus transmission theories changed from droplet and surface transmission to airborne transmission during the pandemic


When the coronavirus started in late 2019, the prevailing perception of the spread of viral diseases was that the virus infects surfaces as well as as a droplet infection as a result of sneezing and coughing. Soon after the pandemic began, however, fears arose that the coronavirus could spread through the air. The mechanism of infection was rapidly investigated around the world.

A Finnish research team was among the first to predict the mechanism of infection

In early 2020, a 30-person research group was established in Finland to investigate the possibility of airborne transmission of coronavirus. It soon became apparent that the general perception of the spread of coronavirus was deficient. A couple of months later, the research team published a peer-reviewed article that was among the first in the world to predict the fears of airborne infection come true: the coronavirus spreads in the breathing air with small aerosol particles. The observation made during the pandemic was revolutionary - scientists call it a paradigm shift. A similar change was seen in the past in mindsets about the spread of tuberculosis and measles, among others.

The prevailing view was that the coronavirus transmits from surfaces and droplets that fall on surfaces in seconds only about a meter from the source of infection. However, studies have shown that aerosols emitted from the respiratory tract are so small that they remain in the air for hours and can spread over a wide area indoors. The risk is high especially when people speak loudly, sing or breathe.

New information on the mechanism of infection brought changes to the guidelines


At the beginning of the pandemic, citizens were stressed that the most effective way to avoid infection is to wash their hands. At the same time, the use of face masks was even estimated to be a disadvantage. The researchers were concerned about the actions of decision-makers and experts regarding infection control, because the research results showed strong reasons to believe that the coronavirus is transmitted through the air in the form of small aerosols.

Knowledge of the mechanism of infection increased and hundreds of studies around the world began to show similar results about airborne transmission. In the spring of 2021, the medical journal Lancet listed in its article ten arguments why aerosol spread would be the main mechanism of coronavirus transmission. As a result of research, the general protective guidelines against coronavirus began to change gradually, and actions to prevent airborne infections were added to the recommendations.

Air hygiene plays an important role in protection against the virus

The spread of the coronavirus in the air was considered a “horror scenario” at the beginning of the pandemic. However, researchers have realized that airborne infections can be prevented with the right measures. Effective means of preventing infections include face masks and air hygiene, which means reducing viral concentrations in indoor air through effective ventilation and air purifiers.

According to Ville Vuorinen, Assistant Professor at Aalto University, air hygiene will be a growing trend when corona restrictions are lifted and targeted air hygiene could play a role in combating all respiratory infections in the future.

“The virus isn’t going away anywhere yet. People still have to dare to trust that they can go to work, hobbies, events and bars safely, ”says Vuorinen in an article in Helsingin Sanomat.


Source: Helsingin Sanomat 6.10.2021. Finnish researchers understood the mechanism of the virus's infection.


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