YouthAwareIssue10

They are highly contagious so they can spread very easily
from a pre-infected or symptomatic person to a normal
person. It doesn't take a lot to spread— just a cough or a
sneeze is enough to spread those droplets with the viral
particles. So they are all respiratory. They are not universally
fatal, so they don't kill each and every person that
they infect. And this is in a way good for the virus because
if the virus wants to survive, it needs the hosts to live long
enough to spread it to more hosts. So if we ever were to
have a viral infection that killed almost everybody that infected,
that infection would die out pretty soon, because
very soon all the infected hosts would die. And then the
virus would not be able to spread because it could die
along with its host. So those are the two common things is
that it's highly contagious, and people who get it, some of
them survive, and they spread it on to others. Now, the
third thing to keep in mind is these viruses, they have animal
reservoirs. So even if we were to immunize every human
being in this world, these viruses can live in other animals
that we cannot always immunize. So for example, flu
can live in chickens and birds and pigs. And coronavirus
can live in rodents, like ferrets and minks and pangolins. It
can also live in bats, and we are never going to be able to
eradicate it from the wild animal reservoirs in the forests
of the world.