Why is coronavirus so widespread compared to SARS?
There are 3 main reasons:
- The virus itself
SARS is more fierce. Many people were seriously ill when first brought to the hospital. Oftentimes patients were already quarantined or dead before they started to spread the virus. Coronavirus, on the other hand, has a much higher spread efficiency; it is a pneumonia but equipped with a spread ability close to influenza; furthermore, the strongest infectivity happens at 2 or 3 days before onset of the illness. Not to mention those who have been infected yet not showing any symptoms. It is very difficult to find out who has been infected or not.
Also the coronavirus is more adaptable to the environment than SARS- it is extremely resistant to cold, relatively resistant to heat (Coronavirus 56°C or 133°F vs. SARS 38°C or 100°F).
It has a long latency and a wide range of transmission channels, which includes the following so far:
1- Direct / aerosol transmission:
Inhalation of droplets, or aerosols formed by droplets from the infected individual's coughing, sneezing, or even talking. This is why masks are so important- you can never guarantee safe distance between others at all times.
2- Contact transmission:
Contact droplets deposited on surface of objects (such as table or door handle) left by the infected, and then touch the mouth, nose or eyes of a healthy individual.
3- Contact animals:
Contact virus bearing animals and eating under-cooked meat of infected animals can also spread the virus. It can spread not only among humans but also cats and dogs.
These differences can be summarized in the following table:
The craftiness of the coronavirus makes it extremely resource demanding. First, in order to detect a patient, it needs to cover aspects including nucleic acid, imaging (MRI), body temperature, route, and isolation.After confirmation of the diagnosis, there will be medicine, hospital admission, ICU, ventilator, and even artificial oxygenator, which are all very expensive.
In countries of any of the following problems: aging, insufficient funding, and no proper equipment for testing, the medical system is easily overloaded. Once so, patients would have to wait for hospital admission, and mortality will rise.
2 Birthplace
Origin of coronavirus was believed to be Wuhan, China, but then other evidence, such as patients with no international travel experience or outside contact, suggests other possible sources may exist. So arguably it may have multiple origins rather than one.
3 Transportation
Global population mobility has increased a lot over the years. Except for extremely closed or deserted places like North Korea and Antarctica, the entire world is within attack range of the coronavirus.