You may be concerned that a flu shot may trigger a a flare. It is not clear whether there is a link between vaccination and flares, and several studies have shown no increase in flares among lupus patients receiving killed-virus vaccines.
However, common side effects of a flu shot -- low-grade fever, aches and pains -- can be very similar to mild lupus flares, so it may be hard to distinguish between the two. At any rate, the benefits of preventing the flu are thought to far outweigh the risk of a flare.
The vaccine is comprised of inactive (dead) viral organisms. Studies show that lupus sufferers tend to produce a lower antibody response than those without lupus, but side effects were not more frequent.
Important note: The inhaled “Flu-mist” does contain active (live) virus and should not be taken by lupus patients or those in close contact with lupus patients.
Source: Flu & Pneumonia Shots Lupus Foundation of America. September 2008.