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July 1994

Measles Antibody Titers in Early Infancy

Author Affiliations

From the Division of Neonatology and Infectious Diseases, Departments of Pediatrics and Laboratories, The Hektoen Institute for Medical Research, Cook County Children's Hospital (Drs Kamat, Pyati, Pildes, Jacobs, Luayon, and Muldoon), The Chicago Medical School (Drs Pyati and Pildes), and the University of Illinois College of Medicine (Dr Jacobs) and the Epidemiology-Biometry Program, University of Illinois School of Public Health (Dr Levy), Chicago.

Arch Pediatr Adolesc Med. 1994;148(7):694-698. doi:10.1001/archpedi.1994.02170070032005

Objective:  To determine the prevalence of measles seronegativity among infants younger than 6 months and to ascertain their serologic response to measles vaccine.

Design:  Cross-sectional measles antibody survey during the 1989 measles epidemic in Chicago, Ill.

Setting:  Inner-city perinatal center.

Participants:  Two hundred three infants younger than 6 months who had been admitted to the neonatal intensive care unit at birth; 130 (64%) of these infants were premature. Transplacental antibody transfer was evaluated in a subset of 89 mother-newborn pairs.

Intervention:  Administration of measles monovalent vaccine to seronegative infants.

Measurements/Results:  Measles IgG antibody was measured using indirect fluorescent assay. At birth, 19 (38%) of 50 neonates born at less than 37 weeks' gestation had antibody titers that were twofold to fourfold lower than those of their mothers compared with three (8%) of 39 neonates born at more than 37 weeks' gestation (P<.01). Of the 203 study infants, fewer than 4% were seronegative at birth, while 74% of these infants aged 4 to 5 months were seronegative. Univariate logistic regression analysis indicated that the independent variables related to seronegativity were as follows: gestational age at birth (P=.007), chronological age (P<.001), history of having received three or more packed red blood cell transfusions (P<.001), and maternal age at delivery (P=.001). Multiple logistic regression analysis confirmed the association of seronegativity with chronological age (P<.001), gestational age (P<.02), and maternal age at delivery (P<.001). Seroconversion following administration of the measles vaccine was documented in 11(79%) of 14 infants.

Conclusion:  A significant proportion of 4- to 5-month-old infants who had been admitted to the neonatal intensive care unit at birth lack measurable measles antibody; this population should be taken into account when strategies to control measles are considered.(Arch Pediatr Adolesc Med. 1994;148:694-698)