Health officials are predicting that this year’s flu season could be the worst in a decade, and with the flu shot expected to have less-than- average effectiveness against the predominant H3N2 strain, some experts are calling for renewed efforts to develop a universal vaccine against the deadly disease.
According to reports, last year’s influenza vaccine turned out to be only 20 to 30 per cent effective in preventing people from contracting the flu, but the numbers are trending even lower this time around, with estimates hovering around the ten per cent mark.
“The key thing with influenza is that it’s predictably unpredictable but a few arrows are pointing in the direction that this may be a bit more on the rough side for influenza seasons,” Dr. Isaac Bogoch, a tropical infectious disease specialist at Toronto General Hospital and the University of Toronto, to Global News. “There were more documented influenza cases in Australia compared to last year and the year before, more hospitalizations related to influenza and more deaths,” Bogoch said.
That poor showing combined with influenza’s impact around the globe —seasonal flu epidemics cause three to five million severe cases a year worldwide, along with 300,000 to 500,000 deaths— emphasizes how impactful a universal vaccine could be.
“As we prepare for a potentially severe influenza season, we must consider whether our current vaccines can be improved and whether longer-term, transformative vaccine approaches are needed to minimize influenza-related morbidity and mortality,” say the authors of a commentary last month in the New England Journal of Medicine, who point to vaccine mismatches in recent years which have resulted in low vaccine effectiveness.
“Even in years when influenza vaccines are well matched to circulating viruses, estimates of vaccine effectiveness range from 40 to 60%, which is lower than that for most licensed noninfluenza vaccines,” say the authors.
The problem stems from the influenza virus itself, which has certain proteins on its surface that the body’s immune system can, when exposed to examples of the virus, recognize and begin mounting an attack against. Yet, every year, those proteins go through just enough changes to make the invader unrecognizable to our immune system.
Each year, vaccine scientists attempt to match up their vaccine with purified versions of the protein configuration that’s currently making its way around the world, but constant virus mutations can make the process less effective —hence the push for a universal vaccine that won’t need to rely on protein matches.
And researchers say that they’re getting closer, with Canadian input leading the way. Last year, researchers at McMaster University in Hamilton reported advances in creating a flu vaccine that focuses on the part of the virus closer to its core rather than the constantly-mutating surface proteins.
”It targets an area of the virus that is the same among all types of flus basically, even ones that we’ve thought could never infect humans before so it’s not susceptible to the virus changing,” said Matthew Miller, assistant professor in the department of biochemistry and biomedical sciences at McMaster, to CBC News.
Miller has been collaborating with researchers at the Icahn School of Medicine at Mount Sinai in New York and at the University of Chicago, with clinical trials being the next step and, if all goes well, a vaccine on the market within five to ten years.
“The difference between [today’s] vaccines and the universal vaccine is that the universal vaccine works in way whereby it will still be effective even when the virus mutates,” said Miller.