Rotavirus vaccine and health care utilization for diarrhea in U.S. children.

BACKGROUND: Routine vaccination of U.S. infants with pentavalent rotavirus vaccine (RV5) began in 2006. METHODS: Using MarketScan databases, we assessed RV5 coverage and diarrhea-associated health care use from July 2007 through June 2009 versus July 2001 through June 2006 in children under 5 years of age. We compared the rates of diarrhea-associated health care use in unvaccinated children in the period from January through June (when rotavirus is most prevalent) in 2008 and 2009 with the prevaccine rates to estimate indirect benefits. We estimated national reductions in the number of hospitalizations for diarrhea, and associated costs, by extrapolation. RESULTS: By December 31, 2008, at least one dose of RV5 had been administered in 73% of children under 1 year of age, 64% of children 1 year of age, and 8% of children 2 to 4 years of age. Among children under 5 years of age, rates of hospitalization for diarrhea in 2001-2006, 2007-2008, and 2008-2009 were 52, 35, and 39 cases per 10,000 person-years, respectively, for relative reductions from 2001-2006 by 33% (95% confidence interval [CI], 31 to 35) in 2007-2008 and by 25% (95% CI, 23 to 27) in 2008-2009; rates of hospitalization specifically coded for rotavirus infection were 14, 4, and 6 cases per 10,000 person-years, respectively, for relative reductions in the rate from 2001-2006 by 75% (95% CI, 72 to 77) in 2007-2008 and by 60% (95% CI, 58 to 63) in 2008-2009. In the January-June periods of 2008 and 2009, the respective relative rate reductions among vaccinated children as compared with unvaccinated children were as follows: hospitalization for diarrhea, 44% (95% CI, 33 to 53) and 58% (95% CI, 52 to 64); rotavirus-coded hospitalization, 89% (95% CI, 79 to 94) and 89% (95% CI, 84 to 93); emergency department visits for diarrhea, 37% (95% CI, 31 to 43) and 48% (95% CI, 44 to 51); and outpatient visits for diarrhea, 9% (95% CI, 6 to 11) and 12% (95% CI, 10 to 15). Indirect benefits (in unvaccinated children) were seen in 2007-2008 but not in 2008-2009. Nationally, for the 2007-2009 period, there was an estimated reduction of 64,855 hospitalizations, saving approximately $278 million in treatment costs. CONCLUSIONS: Since the introduction of rotavirus vaccine, diarrhea-associated health care utilization and medical expenditures for U.S. children have decreased substantially.

Influenza-like illness in a community surrounding a school-based outbreak of 2009 pandemic influenza A (H1N1) virus-Chicago, Illinois, 2009.

In April 2009, following the first school closure due to 2009 pandemic influenza A (H1N1) (pH1N1) in Chicago, Illinois, area hospitals were inundated with patients presenting with influenza-like illness (ILI). The extent of disease spread into the surrounding community was unclear. We performed a household survey to estimate the ILI attack rate among community residents and compared reported ILI with confirmed pH1N1 cases and ILI surveillance data (ie, hospital ILI visits, influenza testing, and school absenteeism). The estimated ILI attack rate was 4.6% (95% confidence interval, 2.8%-7.4%), with cases distributed throughout the 5-week study period. In contrast, 36 (84%) of 43 confirmed pH1N1 cases were identified the week of the school closure. Trends in surveillance data peaked during the same week and rapidly decreased to near baseline. Public awareness and health care practices impact standard ILI surveillance data. Community-based surveys are a valuable tool to help assess the burden of ILI in a community.

Reduction of diarrhea-associated hospitalizations among children aged < 5 Years in Panama following the introduction of rotavirus vaccine.

BACKGROUND: In March 2006, rotavirus vaccine (Rotarix, RV1) was introduced into the Panamanian national immunization program. We assessed the effect of vaccine on diarrhea-associated hospitalizations among young Panamanian children. METHODS: We obtained monthly numbers of diarrhea-associated hospitalizations among children aged ≤ 5 years during 2003 and 2008 from 5 health regions in Panama, representing 53% of the birth cohort. We compared the number of diarrhea-associated hospitalizations during the postvaccine years of 2007 and 2008 with the prevaccine mean numbers 2003-2005 among children < 1 year and those 1 to 4 years of age. Administrative data were used to estimate national rotavirus vaccine coverage. RESULTS: During prevaccine years, diarrhea-associated hospitalizations among children < 5 years in the 5 regions averaged 4057 annually. After the vaccine introduction, a decrease in diarrhea-associated hospitalizations of 22% (898 fewer) occurred in 2007 and 37% (1502 fewer) in 2008. Greater reductions were observed during January through June, the months presumed to have high rotavirus activity in prevaccine years (33% reduction in 2007 and 58% in 2008, compared with prevaccine mean). Reduction estimates were similar among infants and those aged 1-4 years of age, even though only 25% of the latter group was likely to have received vaccine by early 2008. Estimated coverage with ≥ 1 dose of rotavirus vaccine among infants increased from 63% at the end of 2006 to 94% at the end of 2008. CONCLUSIONS: RV1 appears to have had a substantial impact on diarrhea-associated hospitalizations among young children in Panama.

Sustained decline in rotavirus detections in the United States following the introduction of rotavirus vaccine in 2006.

BACKGROUND: Following implementation of the rotavirus vaccination program in 2006, rotavirus activity in the United States declined dramatically in 2007-2008 but increased slightly in 2008-2009, despite greater vaccine uptake. To further evaluate impact of the vaccine program, we assessed trends in rotavirus testing and detection during 2009-2010. METHODS: We examined rotavirus testing data from July 2000 to June 2010 from the National Respiratory and Enteric Viruses Surveillance System to compare rotavirus season timing and peak activity in the pre- and postvaccine introduction eras. Rotavirus season onset was defined as the first of 2 consecutive weeks during which the percentage of specimens testing positive for rotavirus was ≥ 10%. To assess trends in rotavirus testing and detection, we restricted the analyses to 25 laboratories that reported for ≥ 26 weeks per season from 2000 to 2010. RESULTS: During 2009-2010, the threshold for the start of the rotavirus season was never achieved nationally or in the North, Midwest, or West. Activity in the South met this threshold but the season duration was substantially shorter and of lower magnitude than in all previous pre- and postvaccine introduction seasons. Nationally and within each region, the peak week was more delayed and the peak proportion of positive tests was substantially lower than all previous seasons. The total number of tests performed declined by 23%, and the number of positive tests declined by 86%. CONCLUSIONS: Rotavirus activity was substantially diminished during the 2009-2010 rotavirus season compared with the prevaccine baseline and the 2 previous postvaccine introduction seasons. These sustained declines over 3 rotavirus seasons reaffirm the health benefits of the US rotavirus vaccination program.

Uptake, impact, and effectiveness of rotavirus vaccination in the United States: review of the first 3 years of postlicensure data.

BACKGROUND: Rotavirus vaccine was recommended for routine use in US infants in 2006. Before the introduction of vaccine, rotavirus was the most common cause of severe gastroenteritis in children <5 years of age in the United States. METHODS: We reviewed published data to summarize the US experience during the first 3 years of its rotavirus vaccination program. RESULTS: Rotavirus seasons have been delayed and diminished in magnitude during the postvaccine era compared with the prevaccine era. Hospitalizations, emergency department visits, and outpatient visits due to gastroenteritis have declined dramatically in children < 5 years of age including in children age-ineligible to have received vaccine, suggesting indirect benefits of vaccination. Rotavirus vaccine has been widely accepted by pediatricians. Vaccine coverage is steadily increasing but remains lower than coverage levels of other routine infant immunizations. CONCLUSIONS: The implementation of routine childhood immunization against rotavirus has rapidly and dramatically reduced the large health burden of rotavirus gastroenteritis in US children. Continued monitoring of rotavirus diarrhea is needed to determine if immunity wanes as vaccinated children get older and to better quantify the indirect benefits of vaccination. Ongoing surveillance will also enable monitoring of the long-term impact of vaccination on rotavirus epidemiology.

Trends in healthcare utilization for diarrhea and rotavirus disease in privately insured US children <5 years of age, 2001-2006.

BACKGROUND: To assess impact of the new US rotavirus immunization program initiated in 2006, robust baseline data on diarrhea and rotavirus disease burden are needed. While several studies have assessed burden in inpatient settings, few data are available for emergency department (ED) and outpatient settings. METHODS: We used the MarketScan databases, a large claims-based data repository, to analyze the health and economic burden of diarrhea-related healthcare encounters in children <5 years in inpatient, ED, and outpatient settings from 2001 to 2006. Because rotavirus testing and coding are not routinely performed, rotavirus burden was estimated by calculating excess diarrhea events during winter compared with summer baseline (winter residual method). RESULTS: Between 2001 and 2006, the average annual rate of healthcare utilization for diarrhea was 1561 per 10,000 children <5 years, with a hospitalization rate of 50 per 10,000, ED visit rate of 180 per 10,000, and outpatient visit rate of 1332 per 10,000. The winter residual method attributed 53% of inpatient, 41% of ED, and 23% of outpatient diarrhea events to rotavirus. By age 5, we estimated that 1 in 74 children are admitted, 1 in 27 require ED care, and 1 in 7 are treated in outpatient settings for rotavirus illness. Median payments for rotavirus in inpatient, ED, and outpatient settings were $3135, $332, and $90, respectively. CONCLUSIONS: Rotavirus causes substantial health and economic burden in US children, especially in ED and outpatient settings. Future monitoring through claims-based data sources should allow assessment of rotavirus vaccine impact on healthcare utilization for diarrhea.