This is from an immunologist at Johns Hopkins University.
Feeling confused as to why Coronavirus is a bigger deal than the seasonal flu? Here is the reason hope this helps:
It has to do with RNA sequencing that is genetics. Seasonal flu is an all human virus. The DNA/RNA chains that make up the virus are recognized by the human immune system, this means that your body has some immunity to it before it comes around each year. You get immunity two way: through exposure to a virus or by getting the flu shot.
Novel viruses, come from animals. The WHO tracks novel viruses in animals watching the mutations. Usually these viruses only transfer from animal to animal (pigs in the case of H1N1) (birds in the case of the Spanish Flu). Once one of these animal viruses mutates, and starts to transfer from animal to human then it becomes a problem, because we have no natural or acquired immunity. The RNA sequencing of the genes inside the virus isn’t human, and the human immune system doesn’t recognize it so humans cannot fight it off.
Sometimes, the mutation only allows transfer from animal to human, for years it’s only transmission is from an infected animal to a human before it final mutates so that it can now transfer human to human. Once this happens we have a new contagion phase. And depending on the fashion of this new mutation, that’s what determines how contagious, or how deadly it will be.
H1N1 was deadly but it did not mutate in a way that was as deadly as the Spanish flu. Its RNA was slower to mutate and it attacked its host differently too.
Coronavirus existed in animals only, and no one really knows for how long. Then one day at an animal market in Wuhan China, in December 2019, the virus made a jump from animal to human. At first, only animals could transfer the virus to a human. But in just two weeks it mutated again and gained the ability to jump from human to human. Scientists call this quick ability “slippery”.
The Coronavirus, not being in any form a “human” virus (whereas we would all have some natural or acquired immunity) rapidly spread. The reason being was because humans have no known immunity and there are no known medicines for it.
And it just so happened that this particular mutated animal virus changed itself in such a way the way that it causes great damage to human lungs.
This is why Coronavirus is different from the seasonal flu, or H1N1 or any other type of influenza. This one is a “lung eater”. It has already mutated again so that we now have two strains to deal with, strain “S” and strain ”L” which makes it twice as difficult to develop a vaccine.
History has shown that fast and immediate closings of public places has helped with past pandemics. During the Spanish flu in 1918 Philadelphia and Boston were reluctant to close events and they were the hardest hit.
Currently COVID19 is hitting older folks the hardest but the genome is so “slippery” experts expect that it will mutate again and again. Please follow the instructions from your local authorities and follow the social distance guidelines and wash your hands regularly.