In studies reviewing nearly 60,000 doses, pneumococcal conjugate vaccine was associated with only mild reactions:

• About 1 infant out of 4 had redness, tenderness, or swelling where the shot was given.
  
• About 1 out of 3 had a fever of over 100.4°F, and about 1 in 50 had a higher fever (over 102.2°F) - usually within the first 1-2 days after injections.
  
• Some children also became fussy or drowsy, or had a loss of appetite.
  

So far, no serious reactions have been associated with this vaccine. However, a vaccine, like any medication, can cause serious problems, such as a severe allergic reaction. The risk of this vaccine causing serious harm, or death, is extremely small.