A contraindication to the administration of a vaccine is easy to understand and follow. The CDC defines it as a “condition in a recipient that increases the risk for a serious adverse reaction.” Administering live vaccines to severely immunosuppressed patients falls into this category. The recommendation is simple: do not give a vaccine when a contraindication is present.
Precaution means just that: a potential problem may exist with the administration of the vaccine. A vaccine may be given despite a precaution if—in the opinion of the clinician, the vaccine’s benefit outweighs the increased risk.
One of the three reasons why the CDC issues a precaution for a specific vaccine overlaps a little with the description of a contraindication. A precaution is listed if a condition “might increase the risk for a serious adverse reaction. . . however, the risk for this happening is less than the risk expected with a contraindication.” This subtle difference could keep you out of court if you elect to give a vaccine with a precaution warning—or it could land you in court should you elect to ignore the listed contraindication when you give vaccine.
The correct answers are: A. Administration might cause diagnostic confusion; and B. Administration may not result in immunity.
In addition to the “might increase the risk for a serious adverse reaction,” A and B are listed by the CDC as the other two reasons a vaccine can get the precaution label. Every vaccine has age restrictions. Except for hepatitis B, none are given to infants younger than 6 weeks and the hep B vaccine is not routinely given to preemies who weigh less than 2000 gm until 1 month of age. Use of a vaccine in an age group not in the package insert is off-label use with its own set of medical-legal risks, and probably should be treated like a precaution in most circumstances.