Article

Transmission of Bordetella pertussis to young infants. Pediatr Infect Dis J

Baylor College of Medicine, Houston, Texas, United States
The Pediatric Infectious Disease Journal (Impact Factor: 3.14). 04/2007; 26(4):293-9. DOI: 10.1097/01.inf.0000258699.64164.6d
Source: PubMed

ABSTRACT Pertussis vaccination has reduced the number of notified cases in industrialized countries from peak years by more than 95%. The effect of recently recommended adult and adolescent vaccination strategies on infant pertussis depends, in part, on the proportion of infants infected by adults and adolescents. This proportion, however, remains unclear, because studies have not been able to determine the source case for 47%-60% of infant cases.
A prospective international multicenter study was conducted of laboratory confirmed infant pertussis cases (aged <or=6 months) and their household and nonhousehold contacts. Comprehensive diagnostic evaluation (including PCR and serology) was performed on all participants independent of symptoms. Source cases were identified and described by relationship to the infant, age and household status.
The study population comprised 95 index cases and 404 contacts. The source of pertussis was identified for 48% of infants in the primary analysis and up to 78% in sensitivity analyses. In the primary analysis, parents accounted for 55% of source cases, followed by siblings (16%), aunts/uncles (10%), friends/cousins (10%), grandparents (6%) and part-time caretakers (2%). The distribution of source cases was robust to sensitivity analyses.
This study provides solid evidence that among infants for whom a source case was identified, household members were responsible for 76%-83% of transmission of Bordetella pertussis to this high-risk group. Vaccination of adolescents and adults in close contact with young infants may thus eliminate a substantial proportion of infant pertussis if high coverage rates can be achieved.

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Available from: Flor M Munoz, Aug 22, 2015
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    • "Although vaccination of infants over the first 18 months of life is common in many countries, including Mexico, there is still a window of time before vaccination can produce its full effect. During this period, newborns are vulnerable if they come in contact with infected people who are actively shedding bacteria (Wendelboe et al., 2007). Even in a country with long-standing universal childhood vaccination, waning immunity makes adolescents and adults susceptible to reinfections with subclinical disease who then become carriers and transmitters of the bacteria. "
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    • "However, infants who are too young to receive a full series of immunizations against pertussis are greatly susceptible to the complications of pertussis infection. It has been estimated that 76–83% of infant pertussis cases are contracted from adolescents and adults with waning immunity, including close contacts and adult family members [10] [11]. Deaths due to pertussis infection occur primarily in children younger than 6 months of age, and research suggests that the B. pertussis pathogen may also contribute to sudden infant death syndrome [12] [13]. "
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