What you need to know:
• This season, the nearly 50 per cent of flu cases in B.C. have been Influenza B
• Influenza B has shown up three months earlier than it typically does
• Stomach flu, a.k.a. norovirus, isn’t technically a flu
• Flu vaccines typically take two weeks develop the necessary antibodies
Just a few weeks now separate the most wonderful time of the year from the most terrible time of the year.
Your bedridden roommate, downtrodden co-worker and man-cold manifesto all point to the same thing — peak flu season is upon us in B.C.
Staffers with Vancouver Coastal Health (VCH) aren’t seeing much in the way of statistical anomalies, as doctors’ visits and emergency department visits for influenza are in line with the historical averages for this time of year. That said, one particular flu strain — known as Influenza B — has shown up three months earlier than it typically does.
“There is no good explanation as to why this is occurring. It really highlights the fact that changes in flu patterns are very difficult to predict,” VCH medical health officer John Harding told the Courier.
Harding notes that predicting flu patterns or the severity of a given flu season is difficult, if not impossible. The most common types of flu viruses that circulate in winter months are two strains of Influenza A, which are referred to as H3N2 and H1N1. This season, the nearly 50 per cent of flu cases in B.C. have been Influenza B.
While flu shots are still available, Harding notes the importance of differentiating flu symptoms with what’s commonly referred to as the stomach flu. Known as norovirus, the condition isn’t technically a flu, but an infection. There are no vaccines to protect against it and antibiotics wouldn’t do the trick either.
Characterized by intense vomiting and diarrhea, norovirus is contracted directly through contact — shaking hands, for example — or indirectly by eating food that’s been contaminated by someone with the infection. Recovery time is usually 24 to 72 hours, and there is no specific treatment for it other than drinking plenty of fluids.
“It’s important to stay home from school or work until you are well for at least 48 hours to make sure you are no longer infectious to others,” Harding said.
Vaccines typically take two weeks to work through the body to the point that the necessary antibodies are developed to fight against the flu. If you haven’t gotten one yet, experts agree it can still be effective.
However, gauging the effectiveness of flu vaccines is not without its challenges. According to Harding, a pair of key variables are at play: the amount of flu cases that are actually tested and properly disseminating if a medical condition is in fact a flu, a separate respiratory ailment or just a common cold.
“We take our best guess at the effectiveness of the vaccine by looking at smaller groups of people who get flu-like symptoms, test them to see if the cause of their illness was actually influenza, and then keep track of whether they got the flu vaccine or not,” Harding said. “From this, we can estimate how effective the vaccine was."
Local flu season stats aren’t available yet, but those in the medical field are looking to Australia as a test case, given that flu season has already come and gone on that continent.
“The overall protection of the flu vaccine to all types of flu in Australia this year was 33 per cent,” Harding said. “However, the vaccine showed very good protection against influenza B at 57 per cent. And given the higher number of influenza B in BC this year, it would be reasonable to expect fairly good protection from the vaccine for B.C. residents this season.”
@JohnKurucz
