TORONTO - Public health interventions and vaccination to prevent respiratory tract infections could reduce the rates of hospital admission for Inuit children, two new studies suggest.

The studies, published online on the Pediatric Infectious Disease Journal website, were led by Dr. Anna Banerji of St. Michael's Hospital in Toronto, who has been researching respiratory tract infections in Inuit children since the mid-1990s.

Inuit children have the highest rate of hospital admission for lower respiratory tract infections in the world, and the studies set out to determine what's causing the children to be so sick, Banerji said Thursday in an interview.

"We were trying to identify the risk factors that increased the risk of admission to the hospital for lower respiratory tract infections in Inuit children. ... We also wanted to identify the viruses associated with (the infections)."

The study, which looked at residents in northern communities, found that smoking in pregnancy increased the risk fourfold, living outside Iqaluit increased the risk about 2.7 times, and children who were full Inuit - with four Inuit grandparents - had almost four times the risk of being admitted to hospital.

"Overcrowding increased the risk about 2.5 per cent," Banerji said. "And if a child was not breastfed, then the risks were about 3.6 times higher. So breastfeeding had a protective effect."

RSV, or respiratory syncytial virus, was the most common virus associated with hospital admissions, she said. The rhinovirus, which usually causes colds, also put some children into the hospital. Many illnesses involved children with more than one virus.

RSV was responsible for about 50 per cent of the admissions to hospital for kids under age two, and about 62 per cent of the admissions of babies under the age of one.

An RSV vaccine does exist, and is about 80 per cent effective in reducing RSV infection in premature children, Banerji said.

But the monthly shots of the Palivisumab prophylaxis vaccine are pricey - costing $6,000 to $7,000 per child per RSV season - so they are restricted to premature kids or kids with significant heart or lung disease.

The second study looked at whether vaccination would be cost-effective versus the expense of evacuating children from remote communities and treating them in hospital.

For example, the one-way cost of flights and hospitalization for a child being flown from a remote community to Iqaluit and then on to the Children's Hospital of Eastern Ontario in Ottawa would add up to almost $20,000, Banerji said.

"What our results showed is that if you give the vaccine to every child in the rural communities outside of Iqaluit, you only have to (vaccinate) between 2.5 kids to four kids to prevent one hospitalization," she said.

About 100 extra children on Baffin Island should be immunized in a season, she estimated.

"It's one of the only places in the world that you can actually save money by giving this expensive vaccine," she said.

"And so based on this, we think that the criteria for Inuit children to be eligible for this vaccine should be enhanced, and that Inuit children less than six months of age in the rural communities should be entitled to this RSV vaccine."

Banerji also noted that public health changes to reduce overcrowded housing, discourage smoking, especially in pregnancy, and encourage breastfeeding could help improve the respiratory health of the children.

And she said the National Advisory Committee on Immunization and the Canadian Paediatric Society are planning to study the findings and review their vaccine policy for Inuit children.

The studies were funded by the government of Nunavut.