Factors Affecting COVID-19 Transmission

The current outbreak of coronavirus disease (COVID-19) caused by severe acute respiratory coronavirus 2 (SARS- CoV-2), continues to spread all over the world. In January 2020, WHO decided to define the outbreak of COVID-19 as a public health emergency of international concern.

The virus is now being present in every continent apart from Antarctica. On March 5, Tedros Adhamon Ghebreyesus, director-general of WHO, the outbreak is becoming very real and it would be the first pandemic that could be actually controlled.

Factors Affecting COVID-19 Transmission


Declaration of the pandemic, combined with clear management guidelines helped every country limit the impact of the disease and bring it more swiftly under control. However, this article will provide more information about the factors affecting COVID-19 transmission and how it transmits. 

Factors Affecting COVID-19 Transmission

How Coronavirus transmits?

The behavior and traits of Coronavirus are highly variable and this makes confusions about how the virus spreads through the environment.

Scientists found that some traits spread more easily through water, others through the air, some are wrapped in layers of fatty molecules that help them avoid their host’s immune system, while others are naked.

WHO states that COVID-19 is caused by the SARS-CoV-2 virus which spreads between people, mainly when an infected person is in close contact with another person. Researches are going about this new virus every day and had found proven evidence on transmission from symptomatic, pre-symptomatic, and asymptomatic people infected with COVID-19. 

What is Symptomatic transmission?

People having symptomatic COVID-19 have signs and symptoms compatible with COVID-19 virus infection. Symptomatic transmission is the transmission from a person while they are experiencing symptoms.

According to the studies from epidemiology and virologic studies, the COVID-19 is primarily transmitted from symptomatic people to others who are in close contact through respiratory droplets, by direct contact with infected persons, or by contact with contaminated objects and surfaces.

Studies conducted on the biological samples from confirmed patients provide evidence that shedding of the COVID-19 virus is highest in the upper respiratory tracts such as the nose and throat. Data also suggests that people may be more contagious around the time of symptom onset as compared to later on in the disease. 

What is the pre-symptomatic transmission?

The time between exposure to the virus and symptom onset is the incubation period for COVID-19. This is on average 5-6 days, however can be up to 14 days.

This period is also known as the pre-symptomatic period. Some infected persons can be contagious in this period. That is, transmission from a pre-symptomatic case can occur before symptom onset.

In rare cases, the pre-symptomatic transmission has been documented through contact tracing efforts and enhanced investigation of clusters of confirmed cases.

Studies found that some people can test positive for COVID-19 from 1-3 days before they develop symptoms/ so people infected with COVID-19 could transmit the virus before significant symptoms develop. 

What is an asymptomatic transmission?

A case confirmed with the asymptomatic transmission is an infected person with COVID-19 who does not develop symptoms. In some countries, asymptomatic cases have been reported as part of contact tracing efforts in some countries. 

How does coronavirus spread?

By understanding how coronavirus spreads and the factors affecting its transmission, you can take the right steps so you don’t get sick and infect others.

Person-to-person transmission

Studies found that COVID-19 spreads mainly from one person to another. This may be through droplets or aerosols of the infected person, maybe through airborne transmission, surface transmission, and fecal-oral.

When an infected person coughs or sneezes, then droplets or tiny particles called aerosols carry the virus into the air. So anyone within 6 feet of that person can breathe it into their lungs. 

Airborne transmission

Studies found that the coronavirus can live in the air for up to 3 hours. If someone who has it breathes out and you breathe that air in, then it can get into your lungs. 

Surface transmission

When you touch the surface that someone who has the virus has coughed or sneezed on, then it is another way to catch the new coronavirus. You may touch any surface that is contaminated and then touch your nose, mouth, or eyes.

Studies have proven that the virus can live on surfaces like plastics and steel for 2 to 3 days. So clean and disinfect, all the surfaces you and your family touch several times a day. 


It’s aren’t sure that whether the infection can spread through contact with an infected person’s stool. The virus particles can be found in infected people’s poop and if the person hasn’t cleaned the hands after using the bathroom, then he could infect things he touches.

So to limit the risk of getting COVID-19, here are some basic precautions.

  • Maintain social distancing and stay at least 1 meter away from others, even if they don’t appear to be sick.
  • Wear a mask
  • Avoid crowded places and events
  • Avoid poorly ventilated indoor locations and prolonged contact with others
  • Open windows to increase the amount of outdoor air
  • Avoid touching surfaces in public settings
  • Clean surfaces with standard disinfectants
  • Clean your hands regularly with soap and water
  • Use alcohol-based hand sanitizer
  • Cover your mouth while coughing and sneezing with a bent elbow or tissue

Scientists and medical experts do not possess a good understanding of which virus characteristics and environmental factors control virus persistence in the environment.

When a new virus emerges and poses a risk to human health, we don’t have a good way of predicting how it will behave in the environment. So it is better to take precautions.       

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