Three-year Follow-up of Vaccine Response in Extremely Preterm Infants

[摘要] Objective . To assess whether the adequate antibody response observed in former extremely premature infants after the primary series of immunizations is sustained after the first booster vaccines.Subjects and Methods . Sixteen former extremely premature (<29 weeks, <1000 g at birth) and 17 former full-term (>37 weeks) infants had sera obtained for antibody titer measurement at 3 to 4 years of age. All had received the primary series and first booster vaccines for diphtheria, pertussis, tetanus, polio, and Haemophilus influenzae type b. Twelve preterm and 14 full-term children had completed the hepatitis B vaccine series.Results . At 3 to 4 years of age, former preterm and full-term children had similar geometric mean titer (GMT) values of antibodies to tetanus, diphtheria, and pertussis. Preterm children had a lower GMT value of Haemophilus polyribosylribitol phosphate (PRP) antibody than did full-term children (0.99 vs 3.06 μg/mL). Fifty percent of preterm and 88% of full-term children had PRP antibody >1.0 μg/mL; 100% of preterm and 94% of full-term children had anti-PRP titers >0.15 μg/mL. GMT values of neutralizing antibodies to polio serotypes 1 and 2 were similar, with 94% to 100% of both groups above protective levels (≥1:8). The difference in GMT values of polio serotype 3 approached significance (29 vs 73); fewer preterm children had protective titer values (75% vs 100%). Among children vaccinated against hepatitis B, 75% of preterm and 71% of full-term children were protected (10 mIU/mL).Conclusions . Preterm children immunized at the recommended chronological ages displayed antibody responses similar to those for full-term children for most immunizing antigens. Responses to PRP and polio serotype 3 were less robust than those of full-term children.

[学科分类] 儿科学