Worried about flu season, vaccines and those breakthrough cases? Your questions answered

Remember that awful flu season last year? Of course you don't. Thanks to lockdowns, closed borders, masking and other measures brought in to curb the COVID-19 pandemic, last year's flu season was basically non-existent.

That's likely to change this year.

Public health authorities are warning thatinfluenza is set to make a comeback, and are urging Canadians to get their flu shot as soon as possible.

But with a number of New Brunswickersstill lining up for or having recently received their first or second dose of the COVID vaccine, some are asking: Is it safe to get two shots in such quick succession? If I'm wearing a mask everywhere I go, do I even need to worry about catching the flu?

And what about all those breakthrough cases of COVID-19 doesn't that suggest the vaccines aren't as effective as we'd hoped?

In an interview with CBC News, Memorial University immunology professor Rodney Russell answers all of these "good questions" and more.

This interview has been edited for length and clarity.

Q: We're still wearing masks, we're not hugging or shaking hands as much, we're practising physical distancing. So why are health authorities expecting this year's flu season to be so much worse than last year's?

A: "Last year this time, we were pretty much in bubbles. We were limiting contact. There were more measures in place, there was a lot less mixing, the events were smaller,restaurants were at smaller capacities. The way we're living right now, it definitely won't keep the flu away. We'll definitely still need vaccines."

Q:Since we've gone pretty much a whole year without the flu, will our immune response be weaker this season?

A: "No, it shouldn't be, because we typically have different strains of the flu coming around each year. So in a way,it's almost like the immune system resets itself every year."

• New COVID cases continue downward trend, but officials urge caution as flu season approaches

Q: How do researchers know which strains of flu we'll be up against this year?

A:"The thing that people don't realize is the strains of fluliterally circulate the globe. So whatever was in, say, Australia last year or in the southern hemisphere last year is usually coming at us in our northern hemisphere this year. So they would be monitoring what strains of flu were around and then design the vaccines based on whatthey think might be coming. And if they predict wrong, they can pivot pretty quickly and make a version more aligned with what actually shows up."

Q: How effective is the flu vaccine?

A:"It has ranged from 40 to 60 per cent over the years. Partly because it's a guess, we're never sure of exactly what strains are coming," and partly because some people, such as the elderly, do not develop as robust an immune response.

Q:For those who've only recently had a COVID shot, or who are about to get one, should they be concerned about getting a flu shot so soon afterwards? Or at the same time?

A:"There really shouldn't be any concerns. And the reason I say that is because we already mix vaccines. The MMR vaccine that we all got as kids is actually three different vaccines. It's the measles, mumps and rubella vaccine. So we've already been getting mixed vaccines in the same syringe in the same shot fordecades. The immune system has quite the broad workload capacity, and it can handle two or three things the same time and they don't interfere with each other."

Q: Does the COVID vaccine provide any protection against the flu?

Q:"Absolutely not. They are very, very different things and one wouldn't provide protection for the other."

Q: What about the rising number of breakthrough COVID-19 cases? As of Friday, 23 of 60 New Brunswick COVID-19 patients who were hospitalized were fully vaccinated. Doesn't that suggest the vaccine isn't working the way we'd hoped?

A: "Well no vaccine is 100 per cent.Because we were in a pandemic situation and people were dying by thethousands, we couldn't wait for the perfect vaccine that locked the door completely on the virus. But we had vaccines that kept people alive.

Some people who got vaccinated will still get infected. But we're seeing now that older people who got vaccinated six to eight months ago, their antibody levels are going down. So we're actually seeing the majority of the breakthrough cases that result in death are older people, unfortunately, and older people who also had other health complications,diabetes or other issues that affect your immune system."

Q: So these people would be good candidates for a booster shot, then?

A:"Exactly. They're what I call the vaccinated vulnerable. You know, when we started vaccinating, we vaccinated based on age, whether they were immunocompromised, people working on the front line. But now we're six, seven, eight months post-dose, and the vulnerable are becoming vulnerable again. So those are the people I'm worried about now."

• N.B. COVID-19 roundup: Free rapid tests for home use expands province-wide, 2 more deaths

Q: Is there any data on whether certain vaccines, or mixes of vaccines, result in more breakthrough cases?

A:"With breakthroughs, it's not going to be because of the vaccines, it's going to be because of the timing.So if you got two shots of an early vaccine in January, six months later you're going to be at risk for breakthrough. Whereas if you got a shot of Pfizer in January and then waited three months and got your second shot of whatever in April, well, then yoursix months is coming up in October instead of July."

Q: What would you advise someone who had their shot six months ago or more?

A: "We're really at a place now where there's no one-size-fits-all on on advice. Everybody has to look at their own individual risk of exposure and their own vaccine schedule and say, 'OK, how long ago did I get my second shot and how old am I? And do I have other health complications?' So when the family is gathering forChristmas and you got your second shot nine months ago, well, then you should have your mask on all Christmas. You shouldn't be around your children or your grandchildren without a mask on because your antibodies could be going down and you don't know it. And then you're at an increased risk."

Where, when and how to get your flu shot

When is flu season?

Typically October into early January.

What age groups are eligible for the flu shot?

Anyone six months of age or older can get their flu shot. And anyone 65 and older can get an enhanced high-dose influenza vaccine, which gives older people a stronger immune response and extra protection.

Where can I get it?

The flu shot is availableat most New Brunswick pharmacies.Residents can also be immunized at a variety of clinics offered at community health centres or through other primary-care providers such as physicians, public health nurses, midwives and paramedics.

Do I need an appointment?

Contact your pharmacy in advance. Most will require you to book an appointment, some will have walk-in availability.

Is it free?

Yes.Flu shots are available free of charge to New Brunswickers as part of the province's Universal Flu Vaccination Program.