Last year, the flu vaccination was not effective, because it targeting a different strain of flu to the ones which proved most common.
Dr Humphrey said the type of flu being seen in Canterbury was different to the strains in other parts of the country.
"Had Canterbury not had such high rates of vaccination, it is likely that we would also have experienced high rates of infection from other influenza strains, like the rest of New Zealand," he said.
Canterbury had the highest vaccination rate in the country this year, with 176,690 vaccines distributed as of June.
Age Concern Canterbury chief executive Simon Templeton said a lot of older volunteers had to take time off over the past few weeks because they were down with the flu.
"We were actually talking about it only three weeks ago, saying it has been a quiet season, and then everyone seemed to come down with it at once," he said.
But he believed the vaccine was working.
"If younger people get vaccinated it is protection for the older people in our community," he said.