Recently, 2021-22 saw a long flu season in the United States. Do you have a sense on the type of flu season, possibly severe, we might face this year?
Yes, but severity and longevity of the season are two different things. Longevity-wise, the last few years have been pretty standard flu seasons. It typically begins late in December with peak months being January and February and then cases coming down. One thing to note, though, is that the season typically lasts between December and the end of April.
But what’s quite interesting about that is there are two types of influenza that circulate in humans – influenza A and influenza B. Influenza A is the one that peaks first, while influenza B tends to be on the back end of the season, peaking around late February and into March, then going into April.
COVID cases have surged in late summer and into fall. Is this trend expected to continue, and will it adversely impact the flu season?
That’s kind of a difficult question, and I think there are a few ways you can look at it. Does the fact that there’s an outbreak of COVID impact the severity of flu? The answer to that is no. These are two different viruses. It’s not common to get infected with more than one virus at a time, so there aren’t really concerns on that front.
The bigger concern is you get infected with one and then a few weeks later you get infected by the other one, which certainly is not uncommon and makes for an unhappy person. It’s not necessarily going to make your flu infection worse or make your COVID infection worse that they’re co-circulating together. It’s just that you could potentially get two respiratory viruses in a relatively short amount of time that may make you not feel great.
The other thing, from a healthcare standpoint, is we certainly know that these respiratory infection seasons can be very draining on hospital resources, beds, things of that nature. Getting a flu vaccination is a great way to help prevent yourself from being hospitalized and contributing to that surge.
Moderna is working on a vaccine that the company says will offer, in a single shot, protection against both the coronavirus and influenza viruses. What do you think of this development?
So currently, with the clinical trials of at least the flu vaccine – the one using Moderna’s mRNA technology – there’s really not any difference in the efficacy compared to the standard-of-care flu vaccines that we receive.
But where it can be very attractive is that it’s one shot – you don’t have to get multiple injections, especially if you’re afraid of needles. It also simplifies booking because you’ve just got to book one vaccine, one trip. It’s more convenient, and the immunity you get from it is going to be similar to getting the vaccines separately.
Is there any benefit to getting the COVID booster and the flu shot at the same time?
The recommendation is that you get both, and the CDC says that there’s no problem with getting them at the same time. For convenience, I would definitely recommend just going and getting them at the same time.
Why is the flu vaccine formulated as a trivalent this year, as opposed to the quadrivalent of recent years?
So, it means it’s going to be for H1N1 and H3N2, which are strains of influenza A, and then one for the influenza B virus. Pre-COVID, we had two distinct lineages of influenza B viruses – one was B/Yamagata lineage and the other was B/Victoria lineage. The B/Yamagata lineage has not been observed since March 2020, so people in the flu field are very optimistic that, because of the COVID precautions put in place, the virus ended up going extinct. And importantly, influenza B is only in humans, and so if it’s not in us, then it likely has gone extinct. So, people are quite excited about that.
Just to note, if you looked at the ratios of influenza B infections pre-COVID, it was 90 to 95% B/Victoria lineage and only about 5% B/Yamagata. So, because it was already a small amount, those precautions were put in place and now we think it’s gone extinct.
It takes a lot of time to grow these viruses to make the vaccines, so (by dropping the B/Yamagata strain), it’s going to decrease the amount of time it takes to make these vaccines. It’s going to decrease the price because (the formulation) is three-quarters of what it used to be.
In the last decade, the B/Yamagata strain also evolved very slowly, and we don’t have any evidence that it’s still around, so why keep it in the vaccine?
What are some general practices that people can do to avoid getting the flu during the respiratory virus season?
So, the main one, of course, is to get the flu vaccine. Also, wash your hands frequently, especially during flu season, and try to avoid touching things like your face. Also, it’s important to be aware of situations where you’re around people who could be infected. If you’re going to the doctor’s office, it’s not a bad idea to put on a mask, especially during respiratory season. Similarly, if you are going to the clinic because you’re not feeling well, just wear a mask. Try to prevent that onward transmission.
There is an analogy of the flu vaccine being like a seatbelt. To a degree, it can prevent you from getting infected, but it can’t completely stop you from getting in a car crash. You’re going to get exposed to these things, and it can help you try to avoid getting really sick, or injured in the case of a seatbelt.
