Young Infant Measles Risk Factors: Urban African Area With High Measles Vaccination Coverage

The Pediatric Infectious Disease Journal
August 2011 – Volume 30 – Issue 8  pp: A9-A10,633-728,e130-e154

Original Studies
Risk Factors for Measles in Young Infants in an Urban African Area With High Measles Vaccination Coverage
Balé, Carlito; Garly, May-Lill; Martins, Cesario; Nielsen, Jens; Whittle, Hilton; Aaby, Peter
Pediatric Infectious Disease Journal. 30(8):689-693, August 2011.
doi: 10.1097/INF.0b013e31821786a4

Background: We examined risk factors for measles infection before measles vaccination at 9 months of age in Guinea-Bissau.

Methods: Among 1524 children enrolled in a trial of early measles vaccination at 4.5 months of age, we assessed the relative risk (RR) of measles before enrollment and the incidence rate ratio between 4.5 and 9 months of age for different groups.

Results: The incidence was high, with 4% having measles before 4.5 months and 10% having measles between 4.5 and 9 months of age. The main risk factor was the age of the mother; children of young mothers (age, 15–24 years) had lower antibody titers and higher risk of measles than children of older mothers both before 4.5 months (RR = 1.74 [1.02–2.96]) and between 4.5 and 9 months of age (incidence rate ratio = 1.59 [1.05–2.41]). Having no Bacillus Calmette-Gué;rin scar was associated with a higher risk of measles before 4.5 months of age (RR = 2.61 [1.54–4.45]). Children who were not breast-fed and had fever or respiratory infection at enrollment had a 2- to 4-fold higher risk of measles between 4.5 and 9 months of age.

Interpretation: Young mothers transmit lower titers of antibodies to their children and an increasing proportion of infants become susceptible to measles before the age of measles vaccination.