Up to about half of people who get meningococcal vaccines have mild side effects, such as redness or pain where the shot was given. If these problems occur, they usually last for 1 or 2 days. Mild side effects are more common after MCV4 than after MPSV4. A small percentage of people who receive the vaccine develop a fever. Serious allergic reactions, within a few minutes to a few hours of the shot, are very rare.

There have been a small number of reports of adolescent vaccine recipients who experience Guillain-Barre Syndrome (GBS) shortly after vaccination. While the CDC cannot yet determine if it is the vaccine that truly caused GBS, they are investigating it further. Click here for more information.