Hey everyone,
today we're going to talk about the flu vaccine and
why we need a new flu shot every year.
Vaccines are an important tool that humans have used for
hundreds of years to protect people against many harmful or
deadly diseases.
Vaccines are able to protect us by allowing us to
create immunity against specific diseases or pathogens.
In order to stimulate this immune response,
vaccines typically contain a weakened or killed version of a
pathogen,
and they usually take the form of a shot;
however,
vaccines can also come in the form of a nasal
spray.
The influenza shot or the flu shot contains inactivated
influenza virus particles that cause an immune response in your
body.
Your body's immune system
is able to remember different viruses,
so when it encounters the same type of influenza,
your immune system knows how to deal with it.
Influenza is a virus about 100 nanometres in size which has over
10,000
times smaller than a grain of rice.
Viruses are unlike human cells or bacterial cells, because viruses
need to be inside of another cell in order to
replicate and spread.
So how do viruses, or in this case,
influenza enter and infect human cells?
Influenza has a protein on its surface called hemagglutinin.
This protein is incredibly important for influenza because ultimately it
is what allows influenza to enter your cells. On the surface
of our cells,
we have a molecule called sialic acid that sticks out.
Hemagglutinin on influenza virus
particles interact with the sciatic acid on our human cells,
and this interaction grants influenza entry into our cells.,
where it is able to make more copies of itself and
spread. Now we know that hemagglutinin and sialic acid may be unfamiliar words, and that is ok
And we don't expect you to remember them.
The main thing we want you to know is that
they are key players on the virus service in and
our human cells and they interact with each other.
The general purpose of the influenza vaccine is to make
your immune system produce an immune response against influenza,
and commonly the target of your body's response is the
hemagglutinin protein.
If your body's immune system
can figure out how to inactivate hemagglutinin on influenza particles,
influenza no longer has a way to
enter your cells. After getting vaccinated, your body
can produce a response that does exactly that.
In order to survive,
viruses make millions,
even billions of copies of themselves over time.
However,
as the virus duplicates,
its genetic information undergoes
copying errors.
Imagine if you were tasked with drawing the
same picture many,
many times.
Each time you draw the picture,
it would look slightly different from the rest.
This is similar to what happens when the virus replicates itself.
These errors are not intentional, but they do happen.
Overtime,
these errors can lead to an alteration in the virus'
surface proteins
and it is these proteins that our immune system
uses to recognize and fight the virus.
Influenza better known as the flu is one of the
fastest changing viruses, and by the time flu season comes
back around,
the flu is very different than it was previously.
So why do we need a new flu shot every
year? As we discussed previously,
the flu is always changing and the virus has lots
of time to change in the span of a year.
A new flu shot is created each year to include
the virus strains that are expected to circulate in the
upcoming season.
This means that the strains
in this year's vaccine may be different from the strains
in last yea's vaccine.
In order to develop new vaccines,
it is important to know what the flu most recently
looked like. Located around the world are influenza surveillance centers
that annually monitor the most common strains allowing for the
collection of data and identification of new and evolving strains.
Once the information has been collected,
the World Health Organization
selects the three strains
most likely to circulate during the following flu season and
create a flu shot accordingly.
This flu shot then undergoes testing to ensure that it
is safe and effective.
After it passes these tests, the distribution of the flu shot will
begin.
Thank you for watching!
We hope that this video gave you a better
understanding as to what the flu shot is and why
you should get a new one each and every year.