A program that began in 2011 to immunize babies in Ontario against rotavirus appears to be leading to a big drop in hospitalizations and emergency room visits from the nasty stomach bug.

The new study from researchers at Public Health Ontario and the Institute for Clinical Evaluative Sciences (ICES) found a 71 per cent drop in hospitalizations after the vaccine program began and a 68 per cent drop in emergency room visits.

Rotavirus causes a severe stomach infection, with vomiting, diarrhea, fever and dehydration, says the study’s lead author Dr. Sarah Wilson, who is a medical epidemiologist at PHO and an adjunct scientist at ICES.

“Any parent or caregiver who has cared for a child with rotavirus knows how unpleasant it is and how ill children can get,” she said in an interview.

Rotavirus is really one of the more severe forms of viral gastroenteritis, Wilson said.

“Kids who have it as opposed to other gastrointestinal ‘bugs’ tend to be sicker, they are more likely to be hospitalized, they have a longer duration of illness and they can get quite sick,” she said.

The virus is also highly contagious and can easily spread to other family members when one child becomes infection.

For her study, Wilson’s team looked at data from 2005 to 2013 involving more than 864,000 hospitalization and emergency department records for rotavirus infection and acute gastroenteritis in Ontario.

They focused on the time before the introduction of the province’s rotavirus vaccine program, and afterwards.

Wilson says her study noted a significant drop in the number of babies and toddlers who had to be hospitalized or taken to the emergency room from rotavirus – a finding they had expected.

“But we were really pleased to see there was an impact in older siblings as well,” she said.

There was even a drop of hospitalization and ER visits in adults and older adults. Together, hospitalizations dropped by 20 to 38 per cent among all age groups, including older children,adults, and adults over 65 years of age.

“We’re not the first study to note this, but there is accumulating evidence from other countries that have had rotavirus vaccination programs for a while that the ‘herd effects’ are quite prominent and extend up to older adults,” she said.

The full results appeared in the journal PLoS One.

Ten of Canada’s 13 provinces and territories now have publicly funded rotavirus vaccination programs. Since the infection is most common among infants and toddlers, it is offered early, at two months of age and again at four months.

“One of the nice things about the vaccine is that it is an oral vaccine, so it’s a sweet sugary solution that is given in a baby’s mouth when they come in for their well-baby checkups,” Wilson said.

With this study, Wilson says she feels she has good evidence that the vaccination program is working to reduce serious illnesses that lead to hospital visits, not only in babies but in older members of the community as well.

“This research clearly shows how effective a public vaccination program can be at protecting babies and kids from getting sick and alleviating burden on the health care system,” she said.