Vaccine Fatigue, Misinformation Could Impact Flu Rates, Expert Says

Zachary Nelson, PharmD, BCIDP, BCPS, discussed the past 2 influenza seasons and how they could help predict vaccination and illness rates.

Aislinn Antrim: Hi, I'm Aislinn Antrim with Pharmacy Times. Today I'm speaking with Zach Nelson, an infectious diseases and emergency medicine pharmacist at Abbott Northwestern Hospital, about influenza and what's potentially been missed over the last couple years while we've been focusing on COVID so much. And so, the flu has largely kind of been put on the backburner compared to somewhat normal times. Can you give an overview of what the past flu season has looked like and what you've seen?

Zachary Nelson, PharmD, BCIDP, BCPS: Sure. Well, typically, the CDC estimates the burden of influenza on a yearly basis, using a combination of data from their various surveillance systems that look at symptomatic illnesses, medical visits, hospitalizations, and deaths. However, during the past influenza season, the number of people hospitalized with flu is too low to generate accurate estimates of what was going on. So, we don't have precise estimates as to the true burden of influenza this last season. But the data we do have suggests that the flu activity last season was the lowest it has been since the current system of reporting began 25 years ago in 1997. So, one way we can get a sense as to just how much of an outlier last season was is to look at the positivity rates from clinical lab samples. So, in the 2019-2020, season, the year prior to last, the positivity rate was about 15% to 20%. Last year is about 0.1% to 5%. And additionally, we can look at hospitalization rates, and those were down significantly as well. So really, overall, a historically low burden of influenza this last year.

Aislinn Antrim: Very interesting. What have vaccination rates looked like for influenza vaccines? And how has that impact been seen on these rates of illness?

Zachary Nelson, PharmD, BCIDP, BCPS: That's a good question. I think, you know, what we've seen over the last decade or so has been a gradual increase in the vaccination coverage for influenza. When we look at the general population, from about 43% or so in 2010, to most recently, last year, about 52%, preliminary information for this year would suggest that in just about every category, the vaccination rates are lower this year. And I think that's one reason why the CDC has stressed in their communication that influenza vaccines can be given at the same time as COVID-19 vaccines. You know, there's an effort to capture these patients when they're interacting with the health care system, because for some people, that's not very often.

And I think what we're seeing too, is that, you know, the social determinants of health and health disparities are also making an impact this year, just like they do every year in the sense that vaccine coverage amongst, you know, white children, and then non-white children and adults—it's a lot lower amongst those that are not white. And so, we still have quite a bit of work to do in that area, as well as with pregnant patients. And so I think it's a good opportunity, too, for us to say thank you to our community pharmacy colleagues who have shouldered such a huge burden in terms of vaccinating the country against COVID-19, while still being there, on a daily basis for their patients, often in suboptimal working conditions, to manage and still administer millions of influenza vaccines on top of everything else that they do. So, in terms of illness this year, you know, certainly we're seeing more than we did see last year, however, nothing close to what we saw in the seasons prior to the pandemic, in terms of positive tests and hospitalization rates and things like that.

Aislinn Antrim: Very interesting. And there was some discussion in the summer of 2021 that the low flu rates in the 2020 and 2021 season could cause a stronger flu season this year, perhaps because immune systems might be a little weaker, or various causes. Did this turn out to be true and kind of what do you see there?

Zachary Nelson, PharmD, BCIDP, BCPS: Yeah, as you mentioned, there was some question as to whether or not the prolonged absence of ongoing community exposure to flu might lead to lower levels of population immunity, especially amongst younger children, and thus perhaps more widespread and severe influenza this year. In my opinion, anyway, I don't think we're really seeing that play out. At least in terms of hospitalizations, we're seeing much lower rates still, as in about 10 times lower rates of hospitalization this season, than we did in the year prior to last. And so, when we look at the distribution of risk between those different age groups, we continue to see what we've seen consistently in the past, and that is that the very young, so under 4 years old, and the older folks about older than 65, continue to be the highest at risk. And when we compare those rates with the other groups, it appears to be fairly consistent with what we've seen in the past. So, this is not something that I have seen personally play out, and in my opinion it has not come to fruition.

Aislinn Antrim: Good, that's good to hear. With so much misinformation and hesitancy around COVID-19 vaccines, do you predict seeing that spill over a little bit into flu vaccines?

Zachary Nelson, PharmD, BCIDP, BCPS: Yeah, unfortunately, yes. You know, I'm concerned with how prevalent misinformation is—and disinformation at this point, through a variety of sources—that some of these mistruths, especially those perhaps repeated by elected officials who are not medically trained, or even the more sophisticated campaigns like cherry picking or manipulating the vaccine adverse effects reporting system data, will influence people to question not only the COVID-19 vaccine, but also the influenza vaccine, and perhaps even childhood vaccines as well. I think this holds especially true for those without regular contact with the health care system, who may not have, you know, a trusted health care professional that they can ask these sometimes sensitive and, you know, reasonable a lot of times questions to. And so, I think this is a threat that's well known around the world, and WHO lists it as a top 10 threat to global health for a reason. And the influenza vaccine in particular, is perhaps an easy target because they can say, you know, well, it's only 40% effective this year. So, you know, why would I do that? But we know that, especially in children, even if it’s not the exact match of those strains and the flu vaccine is different than the ones that are circulating, we still probably get some protection against severe disease. And so, I am worried about the misinformation piece. And that's a whole, you know, complicated talk in its own I think.

Aislinn Antrim: Definitely. For some patients who, maybe they're not falling prey to the misinformation, but they're just tired of hearing about vaccines, and they've had COVID vaccines, and now boosters. Do you think kind of vaccine fatigue could impact flu vaccine rates?

Zachary Nelson, PharmD, BCIDP, BCPS: Yeah, I do. And I think this is something that I do see, I think, both on the patient side, and then maybe unintentionally, on the provider side as well. You know, I think we're all rightfully very concerned about getting people up to date with their COVID-19 vaccines. But it's easy to allow those other vaccines like influenza, pneumococcal pneumonia, things like that, to fall under the radar, or to not take those MyChart reminders or suggestions from providers about just another vaccine. I think it could be contributing to what we're seeing this year in terms of slightly lower vaccine rates. Again, the CDC is aware of this. And I think they, you know, were intentional about emphasizing that we can give all these vaccines at the same visit. And so, you don't have to continue to come back from multiple visits, especially for patients that have difficulty with transportation and things like that. But yes, I think I'm definitely hearing that from my patients and from colleagues as well.

Aislinn Antrim: Definitely. We're pretty far out at this point from next year's flu season, but what are you anticipating and what should pharmacists be aware of when they're looking ahead to that?

Zachary Nelson, PharmD, BCIDP, BCPS: Yeah, I think I put my crystal ball here somewhere. But I think it's hard to say. It'll be interesting to see what happens, not only for influenza, but for these other respiratory viruses, as well. As the appetite for mask wearing and staying at home when you're sick and remote work and things like that continues to decrease, I think it's possible that we might just see how much taking simple measures like mask wearing reduces the burden of disease, especially with these respiratory illnesses that are spread primarily from the droplets route, like influenza. So, it's hard to predict. And I think what our Australian friends will experience, you know, during their upcoming season—this summer for us—will be helpful in determining what will happen next year. But my hope is that we reinvigorate the education and awareness campaigns about the importance of influenza vaccination, because nobody, especially, you know, children, young children, and our older folks, deserve to die from something that's preventable. So hard to say as you had mentioned, but I'm hoping that with the education and with the awareness campaigns and with some of that information from Australia, that that will get a better sense later this summer as to what to expect next year

Aislinn Antrim: Thank you so much for speaking with me about this!

Zachary Nelson, PharmD, BCIDP, BCPS: Absolutely, my pleasure!