[freedomcrusader]

From The Flu, NIAID Fact Sheet:

Are there possible side effects from the flu vaccine?

You should be aware that the flu vaccine can cause side effects. The most common side effect in children and adults is soreness at the site of the vaccination. Other side effects, especially in children who previously have not been exposed to the flu virus, include fever, tiredness, and sore muscles. These side effects may begin 6 to 12 hours after vaccination and may last for up to 2 days.

Viruses for producing the vaccine are grown in chicken eggs and then killed with a chemical so that they can no longer cause an infection. The flu vaccine may contain some egg protein, which can cause an allergic reaction. Therefore, if you are allergic to eggs or have ever had a serious allergic reaction to the flu vaccine, CDC recommends that you consult with your doctor before getting vaccinated.

[traditionalist]

Okay, I stand corrected. It is possible for some people to get sick from the shot. But the risk to the average healthy person is so tiny as to be negligible.

[Knitebane]

Additionally, if you are allergic to thimerosol, getting a flu shot can cause reactions varying from mild discomfort to violent agony.

Thimerosol is a mercury-based buffer added to many vaccines. It is also used in many contact-lens solutions. Thimerosol reactions can occur suddenly in people that previously tolerated the substance.

If you wear contact lenses and need to use thimerosol-free solutions to keep your eyes from swelling shut, you should not get the flu shot.