Just one natural case of influenza in B.C. during flu season

Photo: The Canadian Press

It was the flu season that wasn’t.

The BC Centre for Disease Control has issued its final influenza bulletin of the season. After testing 75,000 samples, just one naturally occurring case of influenza was detected — in a person who recently travelled out of the country.

“In summary, this influenza season was exceptional in not having actually really happened,” said the BCCDC bulletin, which said COVID-19 prevention measures also stopped the spread of the flu.

Looking deeper at the end-of-season figures, there were 18 influenza samples collected in BC in the period of September 27, 2020 to May 1, 2021 during 75,000 tests. Those 18 samples were collected from 11 people, but 10 of those 11 had recently received the flu vaccine, suggesting vaccine-type rather than wild-type virus.

“Detecting vaccine virus shortly after [flu vaccine] receipt is not unexpected,” said the BCCDC, adding that left one other case imported by a traveller.

By contrast, for the same time period of the past 5 (2015-2019) seasons, there were on average 28,366 tests conducted and 5,605 influenza detections per season.

“Public health measures implemented to reduce the impact of COVID-19 continue to prevent the transmission of influenza virus within the community,” said the BC CDC report.

South of the border, the United States had a similar, non-existent, flu season. Of the 463,000 specimens in the U.S. during the same time period, just 0.02 per cent tested positive.

Influenza detections were also very low in Europe and Western and East Asia while being non-existent in Central Asian and Northern Africa.