Infant Rotavirus Vaccine Reduces Diarrhea-Related Hospitalizations, ED Visits, and Outpatient Visits

Alice Goodman

November 07, 2009

November 7, 2009 (Philadelphia, Pennsylvania) — Even though H1N1 flu is dominating the news and has been the center of attention here at the Infectious Diseases Society of America 47th Annual Meeting, diarrhea kills more children worldwide than the swine flu, warned experts. The pentavalent rotavirus vaccine, recommended for routine infant vaccination in the United States since 2006, is safe and has had a strong effect in reducing diarrhea-related hospitalizations, healthcare use, and expenditures in the United States according to several presentations here.

"Diarrhea-associated healthcare events, particularly hospitalizations, declined after introduction of rotavirus vaccine," said Jennifer Cortes, MD, from the Centers for Disease Control and Prevention in Atlanta, Georgia. "We found greater-than-expected decreases in rotavirus-coded events, given the level of vaccine coverage."

She also said that there appeared to be an indirect benefit from vaccination in preventing transmission of rotavirus infection, as reflected by decreased rotavirus-coded events in older unvaccinated children. For 2007 and 2008, the estimated annual cost savings in the United States were greater than $200,000,000.

Dr. Cortes presented a late-breaking poster on a retrospective study that estimated vaccine coverage and postvaccine rates of healthcare use for diarrhea in 29 million privately insured US children younger than 5 years of age after the introduction of the rotavirus vaccine (July 2007 – June 2008) compared with mean prevaccine rates from July 2001 to June 2006.

As of December 31, 2007, 63% of children younger than 1 year of age had received at least 1 dose of the vaccine compared with 23% of 1-year-olds and hardly any 2- to 4-year-olds. Compared with the period before the vaccine was introduced, the rate of

  • diarrhea-associated hospitalizations per 10,000 children younger than 5 years of age declined by 40% (from 52 per 10,000 to 31 per 10,000) in 2007 to 2008,

  • emergency department visits declined by 14% (from 185 per 10,000 to 158 per 10,000), and

  • outpatient visits declined by 8% (from 1348 per 10,000 to 1245 per 10,000).

During the rotavirus season, decreases in these parameters were even greater, with a 47% decline in hospitalizations, a 20% decline in emergency department visits, and a 17% decline in outpatient visits for diarrheal illness.

Across all age groups (<1, 1, and 2 – 4 years old), rotavirus-coded hospitalizations decreased more than 80%.

Dr. Cortes noted that the effectiveness of the vaccine in this study was lower than that observed in clinical trials and said that continued monitoring is needed to assess future trends.

Nosocomial Transmission of Rotavirus Has Declined

Speaking to an indirect effect of the rotavirus vaccine, a separate poster provides circumstantial evidence for the effect of rotavirus immunization on hospitalizations for community-acquired rotavirus. This study, presented by Evan J. Anderson, MD, from Northwestern Memorial Hospital in Chicago, Illinois, looked at the numbers of hospitalizations for community-acquired rotavirus for September through May for each of the years 2003 through 2008.

"Community acquired rotavirus immunization correlated with a dramatic decrease in the substantial burden of hospital-acquired rotavirus," Dr. Anderson said.

A highly significant 83% reduction (P < .001) in the number of admissions was reported in 2007 and 2008 after the rotavirus vaccine was introduced (from a median of 1.61 per 100 admissions in 2003 – 2007 to 0.28 per 100 in 2007 – 2008). A 70% reduction was seen in 2007 to 2008 in hospital-acquired transmission of rotavirus (P < .001). In contrast, rates of transmission of community-acquired respiratory syncytial virus and influenza remained stable during that time.

Safety of the Vaccine Demonstrated

A comprehensive, rigorous, large-scale, postlicensure study reported at the meeting is reassuring about the safety of the pentavalent rotavirus vaccine. The study included more than 85,000 vaccinated infants in the United States (210,071 doses). No significant association was found between the vaccine and intussusception (intestine being pulled into itself and blocking digestion), Kawasaki disease, or any other health outcome. No diagnoses or patterns of diagnoses were identified that suggested any safety concerns. The study was presented at a poster session by T. Christopher Mast, PhD, MSc, from Merck Research Laboratories, West Point, Pennsylvania.

Support for Global Use

Paul G. Auwaerter, MD, 2009 Annual Meeting program chair and clinical director of the Division of Infectious Diseases at Johns Hopkins University School of Medicine in Baltimore, Maryland, was enthusiastic about the data on the pentavalent rotavirus vaccine reported at here. "The pentavalent vaccine reduced diarrheal illness and reduced hospitalization, and it is safe. We need to roll out this vaccine worldwide, since diarrhea is a major killer in the developing world," he stated.

Dr. Cortes and Dr. Auwaerter have disclosed no relevant financial relationships. Dr. Anderson disclosed financial relationships with Merck, GlaxoSmithKline, Meridian Bioscience, and Clearview. Dr. Mast is a Merck employee.

Infectious Diseases Society of America 47th Annual Meeting: Abstracts LB-35, 1149, 1161. Presented October 31, 2009.

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