Flu cases in Ontario have been slashed by 61 per cent since the introduction of the free influenza vaccine, yet a new study offers some insight on why some have been slow to accept the science behind the shot.

The study, which was conducted through a survey by the University of Waterloo, shows nearly half of those who skip the flu shot are doing so because they question its importance or effectiveness. The survey was conducted to explain why only 34 per cent of Ontarians received the flu shot in 2013 and 2014.

Of those who did not receive the seasonal flu vaccine, 46.8 per cent said they skipped it because they questioned its effectiveness or felt their immune system could handle the flu by itself. Another 19.4 per cent said they did not seek the vaccine for moral reasons, while 14.5 per cent said they avoided it due to past experiences with vaccines. The remaining reasons for avoiding the vaccine did not fit into the survey response model.

The flu vaccine has been provided for free throughout the province since 2000. It has been credited with reducing flu cases by 61 per cent annually, while saving $7.8 million in health care costs.

Approximately 10-12 per cent of Canadians contract the flu each year, resulting in 12,200 hospital visits and 3,500 deaths annually.

Vaccine coverage of 80-90 per cent is required to establish population-wide immunity.

"Our research suggests that the majority of people who do not get the flu shot have concerns regarding vaccine effectiveness, or a belief that they have a strong immune system and won't be affected by the flu," said study lead author Samantha Meyer, a professor in the School of Public Health and Health Systems at the University of Waterloo.

The findings are published in the Journal of Health Communication. Data was collected between August and early September, 2014, in the region of Waterloo, Ont.