Showing papers by "Rosalyn J. Singleton published in 2007"

Invasive pneumococcal disease caused by nonvaccine serotypes among alaska native children with high levels of 7-valent pneumococcal conjugate vaccine coverage.

Abstract: ContextWith routine childhood vaccination using heptavalent pneumococcal conjugate vaccine, one concern has been the potential for emergence and expansion of replacement disease caused by serotypes not contained in the heptavalent conjugate vaccine.ObjectiveTo determine whether replacement disease is associated with the overall decline in invasive pneumococcal disease among Alaska Native children.Design, Setting, and PatientsAlaska statewide longitudinal population-based laboratory surveillance of invasive Streptococcus pneumoniae infections from January 1, 1995, through December 31, 2006.Main Outcome MeasuresIncidence and types of pneumococcal disease in children younger than 2 years.ResultsIn the first 3 years after introduction of routine vaccination with heptavalent pneumococcal conjugate vaccine, overall invasive pneumococcal disease decreased 67% in Alaska Native children younger than 2 years (from 403.2 per 100 000 in 1995-2000 to 134.3 per 100 000 per year in 2001-2003, P<.001). However, between 2001-2003 and 2004-2006, there was an 82% increase in invasive disease in Alaska Native children younger than 2 years to 244.6/100 000 (P = .02). Since 2004, the invasive pneumococcal disease rate caused by nonvaccine serotypes has increased 140% compared with the prevaccine period (from 95.1 per 100 000 in 1995-2000 to 228.6 in 2004-2006, P = .001). During the same period, there was a 96% decrease in heptavalent vaccine serotype disease. Serotype 19A accounted for 28.3% of invasive pneumococcal disease among Alaska children younger than 2 years during 2004-2006. There was no significant increase in nonvaccine disease in non–Native Alaska children younger than 2 years.ConclusionsAlaska Native children are experiencing replacement invasive pneumococcal disease with serotypes not covered by heptavalent pneumococcal conjugate vaccine. The demonstration of replacement invasive pneumococcal disease emphasizes the importance of ongoing surveillance and development of expanded valency vaccines.

The relationship of meteorological conditions to the epidemic activity of respiratory syncytial virus

Abstract: Our aim was to obtain knowledge of how meteorological conditions affect community epidemics of respiratory syncytial virus (RSV) infection. To this end we recorded year-round RSV activity in nine cities that differ markedly in geographic location and climate. We correlated local weather conditions with weekly or monthly RSV cases. We reviewed similar reports from other areas varying in climate. Weekly RSV activity was related to temperature in a bimodal fashion, with peaks of activity at temperatures above 24–30°C and at 2–6°C. RSV activity was also greatest at 45–65% relative humidity. RSV activity was inversely related to UVB radiance at three sites where this could be tested. At sites with persistently warm temperatures and high humidity, RSV activity was continuous throughout the year, peaking in summer and early autumn. In temperate climates, RSV activity was maximal during winter, correlating with lower temperatures. In areas where temperatures remained colder throughout the year, RSV activity again became nearly continuous. Community activity of RSV is substantial when both ambient temperatures and absolute humidity are very high, perhaps reflecting greater stability of RSV in aerosols. Transmission of RSV in cooler climates is inversely related to temperature possibly as a result of increased stability of the virus in secretions in the colder environment. UVB radiation may inactivate virus in the environment, or influence susceptibility to RSV by altering host resistance.

Respiratory syncytial virus season and hospitalizations in the Alaskan Yukon-Kuskokwim Delta.

Abstract: From 1993 to 1996, Alaska Native infants younger than 1 year of age from the Yukon-Kuskokwim Delta region in Alaska experienced a respiratory syncytial virus (RSV) hospitalization rate 5 times higher than the U.S. general infant population rate. This article describes the trends in hospitalization and prolonged annual season of RSV hospitalizations in Yukon-Kuskokwim children from 1993 to 2004 and discusses factors associated with high rates of RSV hospitalization and the impact of interventions to decrease RSV hospitalizations in this population.

Diarrhea-associated hospitalizations and outpatient visits among American Indian and Alaska Native children younger than five years of age, 2000-2004.

Abstract: Background:Diarrhea accounts for many hospitalizations and outpatient clinic visits among children. American Indian and Alaska Native (AI/AN) children have experienced a greater infectious disease burden compared with the general U.S. population of children, although diarrhea-associated hospitalizat