Routine Infant Rotavirus Vaccination Has Dropped Hospitalization Rates

By Lisa Rapaport

(Reuters Health) - Hospitalization rates for children with severe stomach and intestinal problems have plunged since infants started receiving routine vaccinations against rotavirus, a U.S. study finds.

Researchers tracked hospitalizations for children under five before and after the debut of a new rotavirus vaccine in 2006. By 2012, they found a 94% decline in hospitalizations for rotavirus as well as a 55% drop for all gastrointestinal problems, when compared with the average hospitalization rates for these conditions from 2000 to 2006.

"Prior to rotavirus vaccine introduction, nearly every child in the United States was infected with rotavirus before reaching five years of age," lead study author Dr. Eyal Leshem, a researcher at the U.S. Centers for Disease Control and Prevention, said by email. "It is not surprising that with the implementation of highly effective rotavirus vaccines we now observe dramatic declines in diarrheal hospitalizations."

Rotavirus can cause severe watery diarrhea, vomiting, fever, and abdominal pain. Some children can become extremely dehydrated, requiring hospitalization. If untreated, the condition can prove fatal, but an estimated 85 to 98% of children vaccinated against rotavirus will be spared severe effects, according to the CDC.

The virus spreads in stool and can be easily passed from one child to the next when they share toys or food, particularly while children are still in diapers. 

"In addition to unclean hands that result in essentially direct transmission, rotavirus can spread after a child with dirty hands touches toys, doors, etc.," Dr. Robert Reiner, an infectious disease researcher at Indiana University in Bloomington, said by email.

"One infection combined with imperfect sanitation/hygiene can quickly result in many more," added Reiner, who was not involved with the new study.

An older vaccine to prevent the virus, RotaShield, was introduced and withdrawn in the U.S. in the late 1990s after it was linked to intussusception in infants.

Two new vaccines, RotaTeq and Rotarix, were approved for sale in the U.S. in 2006 and 2008, respectively. These vaccines appear safer than the older version, but an estimated 1 to 3 infants out of 100,000 may develop intussusception.

Both vaccines are given to infants in oral drops in multiple doses over several months; RotaTeq is administered three times, while Rotarix is given twice.

By 2012, an estimated 69% of children aged 19 to 35 months had been vaccinated against rotavirus, Leshem and colleagues reported June 9 online in JAMA. More recent estimates suggest 73% of U.S. children are fully vaccinated against the virus.

To estimate the hospitalization rates, researchers used data from 26 U.S. states covering more than 1.2 million children under age 5 hospitalized for gastroenteritis from 2000 through 2012.

For every 10,000 children, about 1 was hospitalized for rotavirus in 2012, compared an average of 16 per year from 2000 to 2006, the study found.

"Rotavirus vaccination rates are high enough to result in an impressive reduction in disease, but not yet high enough to make rotavirus infection and related hospitalizations rare," Dr. Douglas Diekema, a specialist in bioethics and emergency medicine at Seattle Children's Research Institute, said by email.

As more children get vaccinated, though, there will be fewer people capable of spreading the illness to older kids or adults who haven't received the vaccine, said Diekema, who wasn't involved in the study.

"The dramatic decline in gastroenteritis hospitalizations directly attributable to rotavirus infection indicates that rotavirus vaccination is doing exactly what it is supposed to do," Kimberly Shea, an epidemiology researcher at Boston University School of Public Health who wasn't involved in the study, said by email. "It is preventing rotavirus from causing severe gastroenteritis requiring hospitalization in young children."

SOURCE: http://bit.ly/1B49TSX

JAMA 2015.

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About the photo: Transmission electron micrograph of intact rotavirus particles, double-shelled. Distinctive rim of radiating capsomeres. Credit: Bryon Skinner; CDC/ Dr. Erskine Palmer