It is that time of year again. The clinic has flu vaccine so we are now scheduling. This post was originally in 2011. #in
Many parents and patients have questions about the flu shot. One of
the common questions we hear in the office: “Is it possible to get the
flu from the flu shot?” It’s a fair concern. After all, you’re bringing
your child to the doctor to get them or keep them well, not to cause
more harm. If we give you a vaccine, you should feel comfortable that it
is a safe one, especially if it’s one we want to give your child every
year.
So here’s the full story on the flu vaccine: I have to start by
defining flu. The term is used to mean many different illnesses. When we
talk about the flu shot, we are referring to the influenza virus. The
main symptoms of infections with this virus are fever, body aches, runny
nose and cough. Some people with have mild vomiting or diarrhea with
influenza, but it should not be confused with what people call the
stomach “flu” where vomiting and diarrhea are the primary symptoms.
Okay, now onto the vaccine. The influenza vaccine has been made the same
way for many decades. Each year around February, the World Health
Organization looks at which strains are circulating around the globe and
tries to make an educated guess as to which strains are expected the
following year. Most years there are two of the A strains and one B
strain of the virus in the vaccine. Because viruses can only grow inside
of living cells, chicken eggs are infected with influenza virus.
After
the virus has had time to reproduce it is purified away from as much of
the egg parts as possible, leaving just reproduced influenza. The virus
is then broken up, mixing up all the pieces using a detergent. Next
comes the step that makes it impossible to get the flu from the flu
shot. Two proteins from the surface of the virus are purified away from
all other parts of the virus. These two purified pieces of the virus are
then put into a sterile solution to keep them stable. The result: the
flu vaccine.
These purified pieces of the virus are not capable of
causing any infection. It would like going to the junk yard and getting a
few windshields and a few steering wheels and then have someone claim
it could run you over. The parts just aren’t there. This system makes it
so it is 100% impossible to get the flu from the flu vaccine.
The
purified pieces can protect you from the flu, though. When the proteins
are injected, the body recognizes them as foreign and the immune system
makes antibodies to clear them out. The antibodies are kept around for
many months so that if you pick up an influenza virus at the mall in
January; your body is already to fight it off before it makes you sick.
It is possible to have side effects from the shot. After all, we are
trying to fool the immune system into reacting to these proteins as if
they were an invader so the body sometimes acts like it is being invaded
for a few days. Common side effects are soreness at the injection site,
mild achiness and possibly a fever for a day or two, a small price to
pay for protection from a virus that kills about 20,000 Americans each
year.
Re-blogged from by Jay Rosenbloom MD PhD of PortlandPediatrics.
