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immunization is the process of becoming
immune to
or protected against a disease usually
by receiving a vaccine
vaccines stimulate your immune system to
protect you from certain diseases
so you won't get sick or get an
infection
normally the organs and cells of your
immune system defend your body from
harmful germs
such as bacteria and viruses
immune cells are constantly circulating
through your body
they monitor certain substances on the
surfaces of cells
called antigens healthy cells have
different antigens than diseased body
cells
or foreign invaders in the body
immune cells usually ignore the antigens
on healthy cells
but when immune cells come across
antigens on
germs they destroy the germ
afterward the immune cell displays the
germs antigen on its surface
this activates other types of immune
cells to help get rid of the infection
for example some activated immune cells
recognize the antigen on infected body
cells
and then destroy them
other activated immune cells called
plasma cells
make molecules called antibodies
these antibodies travel through your
body and lock on
only to germs that have its specific
antigen
this marks the germ for destruction
then other immune cells attack the germs
that have these antibodies
once the infection is gone some of the
immune cells that were exposed to the
antigen
become memory immune cells
in the future if the same type of germ
infects your body again
the memory immune cells will be ready to
destroy it so you don't get sick
this is called natural immunity
in many cases it will last your whole
lifetime
the problem with getting natural
immunity from having the disease itself
is that some naturally acquired
infections can cause serious
complications
or may even be deadly for example
polio can result in permanent paralysis
or
death measles can cause swelling of the
brain
resulting in permanent brain damage or
death especially in children under age
five
and whooping cough also known as
pertussis
can cause complications such as
pneumonia slowed or stopped breathing
and death especially in babies under one
year of age
while symptoms may not be severe in all
people
it's not possible to know who will be
affected enough to become
very ill or even die
vaccines can protect you from getting
these diseases and their harmful
symptoms
vaccines often contain a small amount of
weakened or killed germs
but some contain genetic material such
as
rna or dna that provide instructions for
your body's own cells to make the germs
antigen
usually you receive a vaccine as a shot
inside your body the germ particles in
the vaccine
teach your immune cells to attack these
germs
this process doesn't make you sick but
it does cause your body to make memory
cells and antibodies for those germs
as a result if that germ infects your
body later in life
your immune system is ready to fight the
infection so that you don't get sick
the main types of vaccines include live
attenuated vaccines inactivated vaccines
toxoid vaccines subunit and conjugate
vaccines
mrna vaccines and viral vector vaccines
live attenuated vaccines use a live but
weakened germs they're most like a
natural infection and provide a strong
disease immunity
examples are the measles mumps rubella
chickenpox
and flu nasal spray vaccines
inactivated vaccines use inactive or
killed germs you may need several doses
or
booster shots over time examples are the
hepatitis a
flu polio and rabies vaccines
toxoid vaccines protect against harmful
substances made by germs called toxins
they use weakened versions of the toxins
called toxoids
you may need booster shots to maintain
protection against diseases
examples are the diphtheria and tetanus
parts of the dtap vaccine
subunit and conjugate vaccines use only
a specific part of a germ
they provide strong immunity to that key
part of the germ
these vaccines may also require booster
shots
examples are the pertussis part of the
dtap vaccine
and the hepatitis b vaccine
instead of using germs or toxins mrna
vaccines contain a special type of rna
called
messenger rna or mrna
mrna instructs your cells to make the
germs antigen
which triggers an immune response these
vaccines do not carry live virus
and do not change your dna examples are
certain covid19 vaccines
viral vector vaccines may use either dna
or
mrna to provide cells with instructions
to make a germs antigen
the genetic material is wrapped in a
different safe
virus to take the instructions into your
cells
these vaccines do not change your dna
examples are certain covid19 vaccines
it's important to know that vaccines not
only protect you
but your community as well many diseases
that vaccines prevent
are spread from person to person when
only a few people in your community are
vaccinated
the risk of a disease outbreak is high
but if most people are vaccinated it's
much less likely for a disease to spread
this is called community or herd
immunity
herd immunity is especially important to
protect people who can't be vaccinated
this includes people with weakened
immune systems
serious allergies or other health
conditions
vaccines protect you your family and
your community from diseases that can be
dangerous
or even deadly
to find out more about vaccines talk to
your health care provider