Before introduction of 7-valent pneumococcal conjugate vaccine (PCV7), Alaska Native children and adults experienced an excess burden of invasive pneumococcal disease (IPD) compared with non–Native Alaskans.¹ The greatest disparity in IPD was among children younger than 2 years for whom the annualized rate (450/100 000 per year) was 3 times higher than for non–Native Alaskan children younger than 2 years who have rates similar to the overall US population.^1,2 Introduction of PCV7 into the routine childhood vaccination schedule resulted in decreases in vaccine-type IPD and consequent decreases in all IPD among US children.^3-8 7-Valent pneumococcal conjugate vaccine was licensed in February 2000 and introduced into the routine childhood vaccine schedule for all Alaskan children on January 1, 2001.⁹ In the first 3 years after PCV7 introduction, vaccine-type IPD rates (from 1995-2000 to 2001-2003) decreased by 91% and total IPD rates decreased by 65% among Alaska Native children younger than 2 years.¹⁰ Additionally, PCV7-type Streptococcus pneumoniae nasopharyngeal colonization declined in rural Alaska Native children and adults, whereas the overall rate of S pneumoniae colonization remained unchanged.^10,11

OBJECTIVE. Before 1991, Alaska Native children experienced one of the highest rates of invasive Haemophilus influenzae type b disease. H influenzae type b vaccine has led to a near-elimination of invasive H influenzae type b disease in the United States. We describe challenges encountered in controlling H influenzae type b disease in Alaska and update the current status of H influenzae disease and carriage in Alaska as lessons to other populations.PATIENTS AND METHODS. We reviewed data from statewide H influenzae disease surveillance conducted during 1980–2004. Vaccine coverage data were based on audits from tribal facilities and the National Immunization Survey. H influenzae type b colonization data were based on 6 carriage studies.RESULTS. After universal infant vaccination in 1991, H influenzae type b disease among Alaska Native and non-Native children <5 years of age decreased by 94% and 96%, respectively. After a 1996 change in H influenzae type b vaccine from polyribosylribitol phosphate-outer membrane protein conjugate vaccine to H influenzae type b oligosaccharide-CRM197 vaccine, the incidence of H influenzae type b disease increased in rural Alaska Natives from 19.8 to 91.1 cases per 100000 per year <5 years of age. During 2001–2004, with use of polyribosylribitol phosphate-outer membrane protein conjugate vaccine, the rate of H influenzae type b disease in Alaska Native and non-Native children aged <5 years decreased to 5.4 and 0 per 100000 per year, respectively. In postvaccine studies, H influenzae type b carriage has decreased in Alaska Native children <5 years of age.CONCLUSIONS. H influenzae type b vaccination has resulted in a dramatic decrease in invasive H influenzae type b disease in Alaska; however, despite high rates of H influenzae type b vaccine coverage, H influenzae type b disease rates among rural Alaska Native children <5 years of age remain higher than the rates among non-Native Alaska and other US children. Equity in disease rates may not be achieved in indigenous populations with the current vaccines unless other environmental and household factors contributing to disease transmission are addressed.

Objective. In 1993–1996, we conducted a nested case-control study to determine risk factors for hospitalization with respiratory syncytial virus (RSV) infection among Alaska Native infants and young children. In the current study, we returned to former RSV case-patients and their control subjects during 1999–2001 to determine whether children who are hospitalized with RSV at <2 years of age are more likely to develop chronic respiratory conditions. Methods. For each former RSV case-patient and control subject from remote villages in southwest Alaska, we reviewed medical records, interviewed parents, performed physical examinations and spirometry, collected sera, and analyzed chest radiographs. Case-patients were identified through surveillance for RSV hospitalization, and matched control subjects without lower respiratory infection (LRI)-related hospitalization were identified. Results. Hospitalization for RSV infection was associated with a significant increase in wheezing, LRIs, and asthma diagnosis during the first 4 years of life. The association decreased with age and was no longer significant by 5 years of age. However, hospitalization for RSV infection was associated with increased respiratory symptoms and increased chronic productive cough at 5 to 8 years of age. Children who were hospitalized with RSV were not more likely at follow-up to have allergies, eczema, or a positive family history of asthma. Conclusions. Severe RSV infection in infancy may produce airway injury, which is manifested in chronic productive cough with or without wheezing and recurrent LRIs. Although the association of RSV infection with wheezing seems to be transient, children remain at higher risk for chronic productive cough at 5 to 8 years of age. RSV prevention modalities may prevent sequelae that occur early and later in childhood.