As provinces and territories get ready to roll out their annual flu-shot programs, new research reinforces the idea that vaccinating little kids could significantly reduce hospital visits during flu season.
The study compared emergency-department visits to children’s hospitals in Boston and Montreal before and after the United States adopted a policy of recommending flu shots for kids aged two to five years old.
Emergency-room visits for flu-like illness – as a percentage of total emergency-room visits for kids of this age group – had tracked pretty closely at the two hospitals in the years before the policy shift. But after the change went into effect in the 2006-07 flu season, researchers found a 34-per-cent decline in the rate of emergency visits for flu symptoms at Children's Hospital Boston when compared to the rate at Montreal Children's Hospital.
“It’s pretty substantial,” lead author Anne Hoen
“It means a lot of kids are being protected and staying out of the emergency department due to influenza. And I think it’s great evidence that getting your flu shot is a good way to protect yourself and also reduce illness in the community.”
The team used the Montreal hospital for comparison because Quebec did not recommend flu shots for children aged two to five at the time. (In fact, it still doesn’t – while Canada’s National Advisory Committee on Immunization made a recommendation for the 2010-11 season that children aged two to four get vaccinated against flu, to date not all provinces have adopted the recommendation.) Quebec provides free flu shots for children aged six to 23 months. (Children under six months aren’t vaccinated against flu.)
In reality, the authors cannot say for sure that the difference they saw was due to flu shots. This type of study cannot offer proof that an effect seen was caused by the intervention being examined; it can only suggest a relationship.
As well, the researchers didn’t have breakdowns on what percentage of children in each city got flu vaccine in the years studied.
And U.S. national data suggest early in the life of the new policy plenty of American parents were not heeding the advice to get their children vaccinated against flu. Data for the 2008-09 flu season that were published by the U.S. Centers for Disease Control suggested only 32 per cent of kids aged two to four and 21 per cent of children aged five through 17 got a flu shot that year.
Still, senior author John Brownstein
“It’s really mind-blowing. And we had trouble processing that finding as well,” Dr. Brownstein admitted. He said they tried “every which way” to disprove the effect, but “nothing could take away that finding.”
Neither of the older groups of children was covered by a flu-shot recommendation at the time in the United States. But it is widely believed small children play a key role in introducing and spreading flu within households, because they are more susceptible to it. The declines among older children may reflect the fact that with fewer little kids getting severely ill, their older siblings might have stayed healthier too.
