Many people erroneously believe they get the flu from the flu shot. Some people may get sniffles or become a little achy a day later. Getting sick one or two weeks after the shot typically isn’t from the flu shot. A person may already be exposed to the flu before the shot (since it is flu season). If this person gets the shot he then gets sick with the flu due to the previous exposure but blames it on the flu vaccine.
Flu shots are given during flu season so inevitably some people have already been exposed. Antibodies from the flu vaccine take about 10 days to build up to offer protection. The flu shot can’t cause the flu since it isn’t a live virus but it can cause a serious allergic reaction, often within 20 minutes, for very few people, particularly those who have a severe egg allergy.
A True Flu Shot Allergy or Allergic Reaction to a Flu Shot
A real allergic reaction to a flu vaccine creates any one of the following or all these reactions. Anyone with these reactions to past influenza vaccines is advised not to take the flu shot without a further medical workup.
- Facial swelling
- Swollen tongue
- Lack of Consciousness
- Anaphylactic shock
- Guillain-Barre syndrome occurred in 1976 after the swine flu vaccination. Only one study today shows its possibility as a 1 in a million chance with current vaccines.
A true allergic reaction isn’t to be confused with passing out from a shot nor to be confused with localized bruising or redness around an injection site. Feeling tired or congested the next day isn’t an allergic reaction either. An emotional or nervous reaction to the shot doesn’t imply allergy nor does an upset stomach.
Those Allergic to Eggs are Warned Against Taking a Flu Vaccine
In the near future flu vaccine will be made from tissue cultures instead of egg protein. Until that time egg proteins from hens’ eggs are used to culture the influenza strain vaccine. This tiny amount can affect someone with a severe egg allergy.
Those who can eat baked goods such as cookies and cakes made with eggs are not considered to have severe egg allergies. Some flu shots such as Fluarix contain minuscule parts of egg protein and are used for those who worry they have a mild allergic reaction to eggs. They can try 1/10 of the vaccine before receiving the rest after no reaction is recorded in the medical or allergist’s office.
Thimerosal Allergy and the Flu Shot
Those allergic to thimerosal can still get the flu shot. Thimerasol is also found in some eye drops and causes superficial irritation and redness for some people. It is used as a preservative in tiny amounts in multi-dose vials of flu vaccine. Pre-filled syringes or single does bottles don’t contain thimerosal.
Latex Allergy and Flu Vaccines
Most flu vaccine vials have a stopper through which the vaccine is drawn. Most brands have a non-latex plunger. Ask to avoid the few that are contraindicated for the latex allergic (Sanofi Brands). Most clinic bandaids are latex free these days but be sure to inquire.
Aside from preventing influenza virus, the flu shot is believed to also decrease the odds of a first heart attack. Infection, a form of inflammation, causes rupturing of arterial plaque. Theoretically preventing this type of infection or inflammation (influenza) minimizes that risk.