Can the flu vaccine give me the flu?
The manufacturing process kills the virus particles in flu vaccine so
it can't cause an influenza infection. Two reasons why it may appear to
cause the flu are:
- A small number of people who get
the flu vaccine get flu-like symptoms 24 to 48 hours later. These are
side effects and not a case of the flu. The side effects don't last long
and don't make the vaccine less effective. For people at high risk of
getting complications from the flu, the benefits of the vaccine far
outweigh the risks.
- The flu vaccine doesn't immediately protect
you from the flu. It takes 10 to 14 days to develop complete
protection. People exposed to the flu or another virus that causes
flu-like illness, just before or just after getting the vaccine, may
still become ill.
TopIs it true that the side effects are worse than the flu?
No, especially for the group which is at greatest risk of illness and
death. Most people experience few or no side effects. A recent study
showed that flu vaccine produces no increase in flu-like side effects or
disability in the elderly. After a flu shot, some patients may be more
likely to blame the symptoms of another illness on the vaccine. Taking
acetaminophen shortly after your flu shot may decrease the frequency of
side effects such as redness, pain and swelling at the injection site.
If you experience rare flu-like side effects, they will usually
disappear in 24-48 hours while the flu can last for 10 days or more and
may leave you feeling unwell even longer. Also, a true case of influenza
always leaves open the possibility of complications, such as pneumonia,
and even death.
Top
Will aluminum and mercury in influenza vaccine cause Alzheimer disease?
There's no evidence that influenza vaccine causes Alzheimer disease.
Flu vaccines used in Canada don't contain aluminum. They contain a form
of mercury called thimerosal, which is also used in eye drops and
contact lens solution. The small amount of mercury you would receive
over a lifetime of annual flu shots is well below acceptable limits set
by regulatory agencies.
Top
Can flu vaccine cause or aggravate multiple sclerosis (MS)?
There's no evidence that influenza vaccine causes MS. Recent studies
indicate influenza vaccination doesn't make MS attacks more frequent or
make the disease worse. In fact, studies show MS patients who get the
flu vaccine have fewer attacks.
Top
Can flu vaccine cause paralysis?
A form of paralysis called Guillain-Barré syndrome has been associated
with vaccination in some flu seasons, but the risk is very small. A
study of the 1992-93 and 1993-94 flu seasons in the US showed about one
additional case of Guillain-Barré syndrome occurred in every one million
people immunized. The risk of severe illness and death from flu is many
times greater.
Top