Vaccinating children against rotavirus may indirectly protect adults too, study finds

(Press-News.org) [EMBARGOED FOR JAN. 24, 2013] Pediatric rotavirus vaccination also indirectly protects unvaccinated adults from the highly contagious cause of severe diarrhea and vomiting, suggests a new study published in Clinical Infectious Diseases and available online. The findings suggest pediatric immunization against the virus may be more cost effective than previously thought, given rotavirus-related health care costs among adults.

Before the vaccine, rotavirus caused an estimated 24 million outpatient visits, 2.4 million hospitalizations, and 453,000 deaths in infants and young children worldwide each year. Following the introduction of the pediatric rotavirus vaccine in the United States, declines in the disease have been seen in both vaccinated and unvaccinated children.

Evan J. Anderson, MD, now at Emory University, and a team of researchers at Northwestern Memorial and Children's Memorial Hospitals in Chicago looked into whether the vaccine's benefits extended to unvaccinated adults. They compared the prevalence and genotypes of rotavirus in stool samples collected from approximately 3,500 adults before widespread implementation of pediatric rotavirus vaccination (2006-2007) with the prevalence in samples collected from 2008 to 2010. The researchers found the number of unvaccinated adults who had rotavirus was almost halved in the years after the vaccine was introduced for use in children in the U.S.

"In adults with diarrhea who see the doctor and who have testing for bacterial infections, we noticed an almost 50 percent decrease in rotavirus," said Dr. Anderson. With previous research estimating $152 million in total adult inpatient hospital charges related to rotavirus each year in the U.S., this latest data may make pediatric vaccination "much more cost effective than previously believed."

Dramatic declines in rotavirus prevalence were evident in both adults admitted to the hospital and in those treated as outpatients. The findings suggest that "vaccinating children can protect adults from rotavirus by decreasing the amount of rotavirus circulating in the community," Dr. Anderson said. Because rotavirus genotypes change from year to year, the researchers also noted that "ongoing surveillance is needed to determine whether this impact is sustained."

The positive effect of pediatric rotavirus vaccination programs on the prevalence of disease among both young and old, vaccinated or not, underscores the need to support and encourage vaccination, Dr. Anderson said. "By improving the health of children, we indirectly improve the health of adults."

###The study is available online. It is embargoed until 12:01 a.m. EST on Thursday, Jan. 24, 2013:

Clinical Infectious Diseases is a leading journal in the field of infectious disease with a broad international readership. The journal publishes articles on a variety of subjects of interest to practitioners and researchers. Topics range from clinical descriptions of infections, public health, microbiology, and immunology to the prevention of infection, the evaluation of current and novel treatments, and the promotion of optimal practices for diagnosis and treatment. The journal publishes original research, editorial commentaries, review articles, and practice guidelines and is among the most highly cited journals in the field of infectious diseases. Clinical Infectious Diseases is an official publication of the Infectious Diseases Society of America (IDSA). Based in Arlington, Va., IDSA is a professional society representing nearly 10,000 physicians and scientists who specialize in infectious diseases. For more information, visit www.idsociety.org.