The Real Danger: The Transmissibility of Coronavirus

09 June, 2020
Coronavirus has rapidly expanded throughout the world and it's essential to know the transmissibility of this illness in order to minimize the risk of contagion. What should we do about it? We'll explain in detail in today's article.

Scientists around the world are in a race against time to slow down the spread of COVID-19. There are a number of different ways to attack this infectious agent, including social distancing, handwashing, preventative measures, the development of vaccines, etc. Right now, to understand how to reduce the spread of this pandemic, it’s important to understand the transmissibility of coronavirus.

However, one thing is sure: we need to know our enemy in order to defeat it. Therefore, among all of the characteristics of any virus, one of the most relevant is, precisely, its transmissibility. Viruses are particles formed by nucleic acids surrounded by proteins. They are capable of reproducing at the expense of the cells they invade.

In general, a virus isn’t interested in killing the host it invades. An effective virus is one that reproduces without its carrier even detecting its presence. That way, the virus can spread among other individuals before producing symptoms that impede normal life.

So, transmissibility is a key term when it comes to facing any epidemic. Therefore, in the following article, we’ll explain the importance of the transmissibility of coronavirus as well as the terminology it entails.

Why it’s important to understand the transmissibility of coronavirus

The Centers for Disease Control and Prevention (CDC) indicate that the ease with which viruses can spread from one person to another can vary. Some viruses are highly contagious, while others are less contagious. In order to understand that the transmissibility of coronavirus is the true danger, we’ll look at the process in detail.

You may also want to read: How Coronavirus Infects Cells in the Lungs

The basic rate of reproduction

How does coronavirus spread?
Scientists estimate that coronavirus has an approximate RO number between 2 and 3. However, the way it spreads represents a real danger.

To put it simply, the basic reproductive rate, or R0, is the average number of new cases that an infected individual will produce over the course of an infectious period. When this value is less than 1 unit, the infection ends up disappearing after a long period of time. However, when it is greater than 1 unit, then continuous propagation becomes a possibility. Let’s look at an example:

The value indicates that a persona with the measles can infect another 15 unvaccinated individuals during the time that he or she is sick. As for the common flu, to add some perspective, the value is 1.3.

Experts estimate that the R0 of coronavirus (COVID 19) is between 2 and 3. So, the transmissibility of coronavirus is twice that of the common flu. However, it doesn’t come close to being as transmissible as the measles. So, if we’ve been living alongside illnesses with greater transmissibility for decades (like the measles), then what’s the real danger of coronavirus?

The incubation period and asymptomatic carriers

On the news, you’ve likely seen a variety of testimonies these days like the following, “Yeah, I have coronavirus but I’m lucky enough to not have any symptoms.” But these cases are a double-edged sword:

  • Statistically, we know that 80% of cases of coronavirus infection involve mild symptoms. These individuals don’t require hospitalization.
  • In China, 43,000 people tested positive for COVID-19 without clear symptoms.
  • The incubation period is between 5 days and 3 weeks, exceptionally, with an average of 7 days. While reports have revealed the carriers can spread the disease during the incubation period, this is not the main period of contagion.

This data is very hopeful on an individual level. It’s possible for people at low risk to catch the disease without even noticing. This is clearly good news for those individuals. However, it’s definitely not good news for members of the vulnerable groups they are in contact with. A state of relative healthiness during the illness period increases the transmissibility of the virus.

Keep reading: Is it Possible to Be Reinfected by Coronavirus?

The effectiveness of going unnoticed

The elderly are more at risk when it comes to coronavirus.

Coronavirus doesn’t produce severe symptoms in every individual, and this is what makes it so dangerous. Since it often goes unnoticed, it can manage to reach more people in the at-risk groups.

If people become seriously ill as soon as they contract the illness, then they should be hospitalized immediately. Indirectly, this minimizes the possibility of them exposing other individuals. Therefore, it’s likely for the R0 of the causative virus to be less than 1.

From a hospital bed, sick individuals can’t move about, much less go about their normal lives. This makes it very difficult for them to spread the infection to even one other person. And this is where the effectiveness of coronavirus comes into play. Many carriers are able to carry on with their normal lives. Even though they have a cough, a headache, or a slight fever.

Who hasn’t gone to the grocery at some point even when they felt sick? It’s a perfectly normal custom. However, this allows the virus to travel in the particles we produce when we cough or sneeze. This transmits the virus to others, some of whom are at greater risk of developing complications. This is the key to coronavirus’s success. It allows seemingly healthy people to go about their normal lives, thus infecting the maximum number of individuals possible.

The importance of detection

For this reason, in recent days, so much emphasis has been placed on the number of quick detection kits. Ideally, any person that’s been in contact with a sick individual should undergo testing… whether or not they show symptoms.

For logical reasons, this process is very difficult. The illness spreads quickly, and time and resources are limited. Therefore, right now, only those who can prove personal exposure to the illness or those who showing clear symptoms and have been in contact with someone who has tested positive are eligible for testing.

This is the true motive behind the need for civil responsibility. We can’t be sure we haven’t been exposed to the virus, but we can minimize the chances of contagion by leaving our homes as little as possible.

So, the true danger of the coronavirus isn’t its mortality rate (which is 4%, almost exclusively among the elderly). Rather, the real danger we’re looking at is the transmissibility of coronavirus. That’s why it’s so important to minimize contact with other people at this time.

 

  • Adhikari, S., Meng, S., Wu, Y. et al. Epidemiology, causes, clinical manifestation and diagnosis, prevention and control of coronavirus disease (COVID-19) during the early outbreak period: a scoping review. Infect Dis Poverty 9, 29 (2020). https://doi.org/10.1186/s40249-020-00646-x
  • Centers for Disease Control and Prevention. (2020). How Coronavirus Spreads. CDC. Available in https://www.cdc.gov/coronavirus/2019-ncov/prepare/transmission.html
  • Majumder, M., & Mandl, K. D. (2020). Early Transmissibility Assessment of a Novel Coronavirus in Wuhan, China. SSRN Electronic Journal. https://doi.org/10.2139/ssrn.3524675
  • Han, Y., & Yang, H. (2020). The transmission and diagnosis of 2019 novel coronavirus infection disease (COVID‐19): A Chinese perspective. Journal of Medical Virology. https://doi.org/10.1002/jmv.25749