C-Reactive Protein (CRP) and Cardiorespiratory Responses to Primary
Immunization in Premature Infants

Massroor Pourcyrous, Sheldon B. Korones, Henrietta S. Bada. Pediatrics, University of Tennessee, Memphis, Memphis, TN; Pediatrics, University of Kentucky, Lexington, KY.

BACKGROUND: We previously reported that in premature infants, primary immunization series with whole cell pertussis vaccine resulted in rise in CRP (100%) and abnormal cardiorespiratory signs (30%).

OBJECTIVE: CRP and cardiorespiratory signs may vary with each specific vaccine produced by different manufacturers.

DESIGN/METHODS: In present study, CRP and cardiorespiratory responses to immunization when all five vaccines were given at once or when vaccines were given in separate days were documented. Immunization was initiated when CRP was normal. Then, CRP was repeated every 12 hours within the first 48 hours of immunization. Cardiorespiratory signs were documented during three days before and three days after the immunization.

RESULTS: One hundred and sixty premature infants received DTaP (Infanrix), H.influenzae (Act Hib), Hepatitis B vaccine (Engerix), Polio vaccine (IPV; Aventis) and pneumococcal vaccine (Prevnar) at 2 months of age. The percentage of infants with abnormal CRP values and cardiorespiratory signs are presented in the following table.

CONCLUSIONS: In premature infants abnormal CRP and cardiorespiratory signs are commonly present when all vaccines are given at once. However, vaccines when administered in separate days may result in fewer cardiorespiratory signs. Increased CRP values following immunization may be a specific response with some vaccines. Immunization with Engerix or IPV does not cause any rise in CRP or cardiorespiratory signs. Since different manufacturers are producing these vaccines, CRP responses may vary based on the products used. In order to be assured that abnormal CRP and cardiorespiratory signs after the immunization are due to the immunization and not to a bacterial infection, immunization should be initiated after determination of normal CRP.

Vaccines    Number of infants   Abnormal CRP    Cardiorespiratory signs
All five vaccines    30                    86%               30%   
DTaP (Infanrix)  42                    31%               12%   
PCV (Prevnar)    27                    52%               7%
Hib (Act Hib)    27                    63%               3%
Hep. B (Engerix) 21                    0%                0%
Polio (IPV)        13                      0%                0%