COVID-19 Is Far Worse Than Other Varieties of Coronaviruses
The good thing is that we know a bit more about this virus than when we had started. And mind you, it has been half a year! But we have not learned enough so that we can stretch our legs. We know that this virus is different from the other varieties of Coronaviruses. But how?
Everything has to do with the underlying epidemiology of the pathogen.
For starters, epidemiology is the study of the distribution and determinants of health-related states and events in specified populations.
In layman terms, it means the study of how this virus reacts in a specified population. We know that it is fast spreading and has low mortality rate. SARS, which is caused by another variety of coronavirus, infected only 8422 people and killed just about 916 before it was declared as “contained”. Covid-19 has already infected more than 18 million and killed more than 7 lakh people.
If you calculate the mortality rate, SARS’s rate was around 11%. It was very deadly, whereas the fatality rate for Covid-19 is just 0.5- 1.2%.
The fatality rate for Covid-19 is just 0.5- 1.2%, but do not let that number fool you!
It is where it all went wrong for us. People and government alike, took things so casually, because they knew for a ‘fact’ that this virus is not ‘deadly’. But define ‘deadly’.
The intrinsic qualities of SARS made the virus harder to spread. It also means that we could contain it more efficiently. There is a number that has a lot of significance when we explain the nature of these viruses. It is called the Ro number or the “Reproduction number”. Reproduction number defines the transmissibility of a virus. To be more specific, it quantifies how many new cases spring from each existing case.
The Ro of SARS and Covid-19 are roughly the same, ~ 2.2 to 3.6
They both have an Ro in the range of 2.2 to 3.6. This makes it more confusing right? If the Ro is same, how is one virus spreading rapidly than the other one?
Even when the above statement is true, the transmissibility of a pathogen need not be the same for every individual. The variation in Ro across individuals can be quantified. This variation has important effects.
A virus with large variation in Ro means that it can manifest with many super-spreaders and super-spreading events. SARS was one such virus. It was estimated that four movements were necessary for one transmission chain to be initiated, the other three would die out. But the variation in R0 for Covid-19 is lower than for SARS, so super-spreading events, though they do occur, are less important than the more frequent chains of transmission.
What makes this all more dangerous is the fact that the people infected with Covid-19 can transmit it even before they develop any symptoms. This makes detection very difficult.
The features of Covid-19 makes it more dangerous than SARS. SARS, though had high fatality rate, was more easily controllable than Covid-19. The world still has no idea about the long term effects of this virus. What if the real impact is something else and fearsome?
We cannot take it lightly anymore. Self-isolation and widespread testing are imperative. We need time to learn about this virus. Once we know the virus, we can defeat it. But until then, we as a civilized society, should co-operate and not defeat others and the people we love.
Wear masks, self-isolate, and get tested if you have any symptoms.