Epidemiology of Haemophilus influenzae Type B Disease among Navajo Indians

• Published in: Public health reports (1974) 1984-07, Vol.99 (4), p.404-409
• Main Authors: Coulehan, John L., Richard H. Michaels, Christian Hallowell, Richard Schults, Thomas K. Welty, Joseph S. C. Kuo
• Format: Article
• Language: English
• Subjects: Adolescent; Antibodies; Bacterial diseases; Bacterial Infections - complications; Bacterial Infections - epidemiology; Bacterial meningitis; Biological and medical sciences; Child; Child, Preschool; Children; Epidemiologic Methods; Epidemiology; Haemophilus Infections - epidemiology; Haemophilus influenzae - immunology; Haemophilus influenzae - isolation & purification; Haemophilus influenzae type b; Haemophilus meningitis; Human bacterial diseases; Humans; Indians, North American; Infant; Infant, Newborn; Infectious diseases; Medical sciences; Meningeal tuberculosis; Miscellaneous; Nervous system diseases; Nervous System Diseases - etiology; Pneumococcal meningitis; Prevention and actions; Public health. Hygiene; Public health. Hygiene-occupational medicine; Specific populations (family, woman, child, elderly...); Tropical medicine; United States; Vaccination
• ISSN: 0033-3549; 1468-2877

During a 7-year period ending June 30, 1980, the annual incidence of all Haemophilus influenzae type b disease among Navajo children less than 5 years old was 214 per 100,000, and that of H. influenzae meningitis was 152 per 100,000. Eighty-one percent of H. influenzae meningitis occurred in children 12 months of age or younger, and 64 percent clustered in children ages 4 through 8 months. Meningitis accounted for 70 percent of all invasive disease. No epiglottitis was observed. The epidemiology is similar to that in Yupik Eskimos, who have an even higher rate of H. influenzae type b disease than Navajos but are a much smaller population. Mortality from H. influenzae meningitis was low (4 percent) among Navajo children, but neurological sequelae were observed in at least 16 percent of the survivors. This high rate of sequelae may be due in part to clustering of cases in infancy. Among normal Navajo neonates, 79 percent had maternal capsular type b antibody titers greater than or equal to 0.15 micrograms per deciliter (μg per dl), and the whole group had a geometric mean titer of 0.51 μg per dl. By age 4 months, when meningitis cases became frequent, only 14 percent of Navajo infants had antibody titers ≥0.15 μg per dl. Twelve of 67 asymptomatic infants (18 percent), each monitored every 2 months, had H. influenzae type b or a cross-reacting organism isolated from the pharynx on at least one occasion before they were 9 months old. Active immunization would be theoretically indicated in this population with high H. influenzae type b exposure and disease, but a vaccine would have to confer substantial immunity in very young infants.