Patients who have cardiovascular disease are at increased risk of serious complications from the flu, according to a new study by Houston Methodist physician researchers.

The study, a review of the existing literature, found that not only are traditional flu-related outcomes (pulmonary complications, hospitalizations and ICU days) worse among some patients with CVD, but infection in those patients also is associated with an increased risk of cardiovascular events (myocardial infarction, stroke, heart failure exacerbation) and both CV-related mortality and mortality from all causes.

The review was published in the Journal of the American Heart Association in August.

Getting the influenza vaccine substantially reduces the cardiovascular risks, even among patients with severe CVD.

Yet, despite a growing body of research demonstrating the connection between cardiovascular events and influenza and international guidelines recommending individuals with high-risk conditions such as CVD get vaccinated, the annual vaccination rate for U.S. adults ages 18-64 with high-risk conditions is only 45%. That's slightly better than the 34% of 18-64-year-olds without high-risk conditions, but nowhere near the 80% of all Americans over the age of 65 who receive the vaccine each year.

Clearly, the general public isn't getting the message.

On a mission to change that is Dr. Priyanka Bhugra, Houston Methodist internal medicine specialist and lead author of the JAHA article. She sat down with Leading Medicine to discuss factors that may be contributing to the lack of awareness and low rates of influenza vaccination among patients with CVD. She also offers research-based strategies that may help physicians and health care organizations move the needle on both fronts.

Q: What is the target audience you are trying to reach?

Well, there are three groups we're trying to reach, really. No. 1 is patients with CVD and patients at risk for CVD. This is a large percentage of all American adults, about 40%. No. 2 is physicians who treat this population of patients. These could be cardiologists or primary care providers. And No. 3, we are trying to approach public health workers in communities and at the national level to work towards educational and outreach efforts for the vaccine.

Ideally, the entire American public should really be aware of these risks.

The general American public seems to be aware of who is in the high-risk categories when it comes to COVID-19. And the general American public seems to be aware that people over 65 are at increased risk of complications and death from influenza, as evidenced by the more than 80% of Americans over 65 who receive the annual vaccine. But, somehow, there doesn't seem to be an awareness that the same people under 65 who are at risk for COVID-19 complications are at risk for influenza complications.

Q: So it's a PR problem? This issue just hasn't gotten enough publicity?

Exactly! We are not sure why the message hasn't disseminated as widely as it should have. The risks associated with CVD and influenza have only fairly recently come to light — in the past 5-10 years or so. There have been several very well-designed studies showing that cardiovascular deaths and influenza spike at the same time; that patients are up to six times more likely to experience a cardiac event in the week after a flu diagnosis than any other time; and that approximately one out of eight patients admitted to the hospital for the flu will experience a cardiovascular event.

There are even more studies out there clearly showing that patients who have received an influenza vaccine are not only more protected against severe respiratory complications from the illness but against related cardiovascular events and mortality as well. And yet you still see this very low vaccination rate of 45% among high-risk adults under the age of 65. Even that 80% of Americans over 65 who get the vaccine each year — those numbers could and should be better.

Clearly the word isn't trickling out through mass media or news coverage of these recent studies.

Q: What other factors are keeping vaccination numbers down?

I think there are a lot of factors. Primary care physicians presumably do know about these studies and the increased risks for patients with CVD or risk factors for CVD. But there are a lot of other things to cover with patients during the course of an annual physical. There's only so much time to go over conditions, medications, referrals, other kinds of vaccinations, etc. And if their annual visit occurs outside of the flu-vaccine season in the fall, it's another step they need to take, either to obtain the vaccine somewhere else off-season or to make sure they're being reminded and coming back in to their PCP's office in the fall for their vaccine.

The pediatric providers do a good job of this generally. And the vaccination numbers for children are typically above 65% each year. That's, again, less than the 90% target we would like to hit, but it's a lot better than this at-risk population between 18-64.

Q: Your article looked at the determinants of who gets their annual flu vaccines. What did you find?

As we've already discussed, younger ages were less likely to get the vaccine, which may be because they have lesser contact with the health care system than their older counterparts. This goes along with certain behavioral factors also associated with not getting the vaccine, namely perceiving yourself to be healthier than you actually are and downplaying the risks associated with the health conditions you have.

Of course, not having health insurance and not having established care in the past are also important factors. Even independent of that, those with lower income, lower education and without enough family support are also significantly less likely to get the vaccine.

Adverse health habits such as smoking and alcohol use are correlated with not getting the vaccine.

And, finally, something that's very familiar and important in the current context of the COVID-19 pandemic: vaccine hesitancy and some of the psychological factors that go along with it — that is, a low perceived benefit of the vaccine and increased perception of adverse effects of the vaccine — also make a person less likely to get an influenza vaccine.

Q: What are some of the strategies you suggest to improve the vaccination rate of this population?

First and foremost, we have to do a better job of educating patients on the extra strain influenza can put on their hearts ... and that the protection the vaccine offers goes even beyond protecting them from the flu. Also, we need to put risks associated with getting the vaccine into perspective for them. Because the internet has greatly exaggerated these risks, some effort needs to be put into counteracting all the falsehoods.

A lot of studies have shown the strongest predictor of getting an influenza vaccination is a direct recommendation from the patient's physician. So educating physicians on the impact they have on their patients is very important.

Some institutional-level or practice-level changes that can certainly help physicians increase vaccination rates include using the electronic medical record system and patient portals like MyChart to set up flu vaccine reminders for patients. Each one of those reminders acts similarly to a direct recommendation from your doctor. That's been found to be very effective.

As far as bigger health care policies, we believe incentivizing practices or primary-care physicians for achieving patient flu vaccination targets could be very beneficial. We also think that setting up the workflow to better allow for flu vaccines could help boost numbers. Typically, primary care practices have a system in place for this, but specialists, including cardiologists, usually do not. This could be a problem for patients who see their specialists far more often than their PCP.

Another recommendation we have is extending the flu campaign period from early fall to early spring. Sometimes, practices run out of the vaccine early, and the added inconvenience of having to go somewhere else makes patients less likely to get it.

In short, we have to target the patients, the providers, the practices, the institutes and the health care systems, as well as be more creative in policy changes in order to increase the vaccination rate and enable people to get the vaccine. It's a big job, but it begins with simply talking about it more.