12/18/2013 07:30 EST | Updated 02/17/2014 05:59 EST

H1N1 virus returns, triggering flu vaccine warning

Health officials in B.C. are advising young people to get a flu vaccine after determining that the H1N1 influenza strain, which circulated during the global pandemic in 2009, has returned to become the predominant strain this flu season.

Young children and people with chronic health conditions are especially vulnerable and should get their flu shot now, said Dr. Danuta Skowronski, a flu expert with the BC Centre for Disease Control.

"The H1N1 virus will appear to most people like the regular flu. Most people will recover. But hospitalizations and death are possible and with H1N1 that's most likely for young people with chronic conditions," Skowronski told CBC News.

Skowronski says H1N1 was a "minor player" in flu strains over the last several years, but this year it has made a comeback.

Public health officials say they aren't expecting the same kind of reaction to the flu strain because people have developed a level of immunity since 2009. In B.C., officials estimate about half the population has some protection.

Still, Skowronski says it's too soon to gauge how effective the flu vaccine is against this year's strain because the virus is constantly changing.

"This virus is in its fifth year of circulation, so we should expect mutations," she said.