Good morning. Because the flu shot is locked in six months early, it missed the strain now circulating through Canada – more on that below, along with a lopsided peace plan in Ukraine and the latest timeline to release the Epstein files. But first:

• B.C. backs a proposal to increase capacity for the Trans Mountain pipeline
• U.S. and Canadian authorities announce new arrests in their efforts to prosecute fugitive Ryan Wedding
• Alaska tribal nations demand a say on Canadian resource projects

When it comes to the flu shot, scientists have to play the long game. It takes at least six months to manufacture the vaccine – more than a billion doses need to be grown in giant batches of eggs – so each February, experts at the World Health Organization place their bets on which flu strains will circulate in North America later that year. But influenza viruses mutate all the time, and sometimes, those bets don’t quite pay off.

That seems to be the case this flu season: The vaccine looks like a mismatch for the dominant strain now making the rounds. Does that mean you can skip the shot altogether? Definitely not, says Lynora Saxinger, an infectious diseases specialist at the University of Alberta – it will still bring down your risk of getting a pretty unpleasant illness. She explains the sort of protection you can expect, why flu seasons are so weird now and whether science can build an even better influenza vaccine.

How do scientists pick the year’s flu vaccines?

They look at which flu strains are emerging and which ones seem to be dominant, so there’s usually H3N2, H1N1 and influenza B strains in the vaccines. But there is some guesswork involved, because flu season in the Southern Hemisphere takes place during our summer, after the WHO has already made its call about what should be in our vaccine. This year, the H3N2 strain that was dominant in places like Australia isn’t part of our current flu shot, and there’s some concern, because it’s a bit of an unknown quantity.

How common are vaccine mismatches?

I think everyone got the notion from COVID that new strains are really bad news, but they’re standard operating procedure in influenza. We often see changes in a strain, sometimes small, sometimes to a greater degree. In this situation, it is a different H3N2 than the one we guessed would be circulating – but as far as I can tell, it doesn’t look like it’s more transmissible or more severe. It’s just less familiar to our immune system.

So should I bother with my flu shot this year?

The influenza vaccine has always been decent – but not excellent – at preventing infection. Its effectiveness ranges from 40 to 70 per cent from year to year. I’d say that’s still worth it, but it certainly doesn’t make you bulletproof. Instead, the vaccine helps reduce your risk of severe illness and hospitalization. That’s the case even in mismatch years, because the flu shot still gives you a bigger deck of cards that you can play against the virus.

I never want to be overconfident, though, in calling which influenza strain will be dominant in any given area, because since the pandemic, flu seasons have been super strange.

Why is that?

Prepandemic, it was quite rare not to have a clearly dominant strain. H3N2 would dominate one flu season, and then the next year, H1N1 would be more dominant, because most susceptible people would have had H3N2.

The pandemic basically interrupted influenza transmission for two years. So, when the world opened up, it got pretty hectic, because people had lost their partial protective immunity. Now both strains tend to be broadly dominant each influenza season, and it hasn’t quite sorted itself out yet. Eyeballing the data so far this year in Alberta, the hospitalizations are divided between H1N1 and H3N2 – even though only H3N2 is suspected to be a vaccine mismatch. That strongly suggests to me that people shouldn’t get nihilistic about a mismatch, because you might still get exposed to H1N1.

Can we build a better flu shot? Would mRNA be useful here?

The attraction of mRNA technology is that it’s quite nimble. We have facilities that have become very adept at producing large volumes of good, quality-controlled mRNA vaccines. I’m oversimplifying, but it’s basically a question of putting in the right code. And so the mRNA sequence can be changed, and the time to manufacture it is much shorter than having to grow a bunch of vaccines in eggs. There were U.S. trials ongoing for different mRNA-based influenza vaccine candidates, but they halted a lot of the research in January.

And then, over the summer, RFK Jr. defunded 22 mRNA vaccine projects worth US$500-million.

The research community is keen to shift those vaccine programs to other countries, but it’s a significant setback. It’s tragic to see an official body undermine confidence in a game-changing – and life-saving – way of preventing infections and treating disease.

There’s a sea of disinformation around mRNA vaccines, but they did not come out of nowhere during the pandemic. These platforms were based on pre-existing research and went through all the usual stages of safety testing. Most people in the world have had an mRNA vaccine now, and I think that’s really important. We have tremendous experience with the safety of these vaccines.

This interview has been edited for length and clarity.