The flu shot works for young children, Ontario health study finds

New research from Public Health Ontario proves that when it comes to protecting young children from the influenza virus, the annual flu shot makes kids 60 per cent less likely to get sick.

It’s that time of year again as public health officials begin prodding and poking Canadians into getting the flu shot.

“Flu is one of those diseases that people don’t tend to worry about when they really should, it’s our number one communicable disease that puts people in hospital and kills people every year,” said Carrie Vossler, a public health nurse with BC’s Interior Health.

Each year, Canada sees an average of 23,000 confirmed cases of influenza, causing 12,000 hospital admissions and 3,500 deaths. Yet the number of Canadians to get vaccinated is still low, with only 34 per cent of adults choosing to do so last year, according to Statistics Canada.

“Influenza can cause serious illness, especially in young children, but there hasn’t been a lot of research that has examined the magnitude of the influenza vaccine’s effectiveness at preventing kids from getting really sick and being hospitalized,” says Dr. Jeff Kwong, scientist in Applied Immunization Research and Evaluation with Public Health Ontario and senior author of the new study which concluded that vaccinated children between the ages of two and four saw their risk of hospitalization due to influenza fall by 67 per cent.

“This research paper helps fill that gap by showing how effective the influenza vaccine can be at protecting young kids against serious complications from influenza infections,” says Dr. Kwong.

Researchers looked at almost 10,000 hospital records spanning four flu seasons for children between the ages of six months and five years old. Of those who had submitted a respiratory specimen for testing, the researchers found that 12.8 per cent were confirmed with the flu virus. On average, children who were fully vaccinated had a 60 per cent lower risk of contracting the disease and that those who received partial vaccination had a 39 per cent less risk of contraction.

The National Advisory Committee for Immunization in Canada recommends that children who are getting the flu shot for the first time in their lives should initially get two doses, with four weeks between doses, in order to achieve maximum benefit. Those that do are said to be fully vaccinated as compared to those who receive just one dose and are referred to as partially vaccinated.

Each year, the World Health Organization makes its recommendations for influenza vaccines, based on predictions about which strain of the virus will be most prominently in circulation. Those predictions aiming to match the vaccine with flu strain are only sometimes accurate, achieving about a 40 to 60 per cent effectiveness rating on average.

Last year’s vaccine against the H3N2 flu virus proved to be only 35 to 40 per cent effective, which is still better than 2014-15’s H3N2 vaccine that turned out to be less than 10 per cent effective.

Along with young children, seniors are another at-risk group when it comes to influenza. Over 80 per cent of seasonal flu-related deaths are said to occur for people aged 65 and older.

The new study was published in the journal PLoS One.