SAFETY, IMMUNOGENICITY AND EFFICACY OF HEPTAVALENT PNEUMOCOCCAL CONJUGATE VACCINE (Wyeth) IN LOW BIRTH WEIGHT AND PREMATURE INFANTS

Shinefield, H, Black S, Ray P, Lewis E, Fireman B,

The Kaiser Permanente Vaccine Study Group¹; Austrian R², Siber G and Hackell J³

¹Kaiser Permanente Vaccine Study Center, Oakland, CA

²University of Pennsylvania, School of Medicine, Philadelphia, PA

³Wyeth Lederle Vaccines and Pediatrics, Pearl River, NY

OBJECTIVE: To evaluate the safety, immunogenicity and efficacy (invasive disease) of the Wyeth seven valent pneumococcal conjugate vaccine in premature and low birth weight infants.

METHODS: Beginning in October 1995, the Wyeth Lederle Heptavalent CRM₁₉₇ (PCV) was offered to infants at 2, 4, 6 & 12-15 mo. in a double blind trial. 37,000 children were randomly assigned 1:1 to receive either the PCV or meningococcus type C CRM₁₉₇ conjugate. Of the total cohort, there were 1762 infants less than 2500 grams and 4313 with gestational age less than 38 weeks.

RESULTS: SafetyLBW and premature infants were twice as likely to be hospitalized as term infants. However, these hospitalizations were due to diagnoses commonly seen in LBW and premature infants and were seen just as commonly in control premature and LBW infants. Except for a slightly increased rate of vomiting and local swelling, reaction rates were similar to those in term infants. Immunogenicity LBW and premature infants responded at least as well immunologically to the conjugate pneumococcal vaccine and in several cases had significantly higher titers than term infants. Disease Risk and Efficacy: Premature and LBW control infants were more likely to develop invasive disease than term controls. However, when the efficacy of the pneumococcal conjugate vaccine was evaluated in these infants, all cases of disease were observed in controls yielding a point estimate of 100% efficacy of vaccination in these premature and low birth weight infants.

CONCLUSION: This heptavalent pneumococcal conjugate appears to be highly effective in preventing invasive disease in premature and low birth weight infants. The safety profile is in general similar to that observed in term infants except for increased local swelling and vomiting both of which were minor and self limited. The vaccine was at least as immunogenic is these infants as in term infants. The seven valent pneumococcal vaccine (Wyeth) offers the potential to reduce the invasive diseasel burden due to the pneumococcus in premature and low birth weight infants.

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