Effect of Infant Immunization on Procalcitonin Levels - A Pilot Study

Study Summary

Fever is a well-known side effect of immunizations. When a febrile infant presents to a healthcare site, such as an emergency room, a large number of tests are usually performed, which may include a procalcitonin (PCT) level. PCT is being increasingly recognized as an inflammatory marker suggestive of serious bacterial infection, and is being used in clinical practice in the workup for acute febrile illness. Based on an elevated PCT level, further testing may be done, antibiotics may be started, and the patient may get admitted to the hospital for observation before identifying the cause of the elevated PCT level. The investigators believe that immunizations can cause an increase in PCT levels in the absence of an acute infection. Thus, a finding of elevated procalcitonin in a recently immunized child may not have the same clinical implication as it does in other clinical scenarios. To investigate this, the investigators designed this pilot prospective study to compare PCT levels immediately before and forty-eight hours after the administration of routine infant immunizations. The investigators will enroll healthy infants presenting for their two, four, and six-month well child visits at FamilyCare - Children's Medicine Center and receiving routine immunizations as recommended by the Centers for Disease Control.