Heart Disease & Flu: A Dangerous Combination
It’s not too late to educate your patients about the link between flu and heart disease and encourage them to get vaccinated.
“Get your flu shot” is a familiar community health campaign. Unfortunately, influenza and its related pneumonia are still among the top 10 causes of death in the United States.1 Other complications of the flu include bronchitis, lung failure, heart attack, and death. So avoiding the flu is certainly reason enough to get the vaccine. But there’s an additional incentive, according to a study published in the Journal of the American Heart Association: the influenza vaccination could significantly reduce the risk of a serious or fatal cardiac event in people with heart disease or associated risk factors.2
The Effects of the Flu on the Heart
Lifesaving Benefits of the Flu Shot for Cardiac Patients
The Houston Methodist review published in the Journal of the American Heart Association reported that the flu vaccine effectively protects adults, making them 82% less likely to be admitted to the ICU for the flu and to have a 37% lower risk of being hospitalized at all.4 Among people hospitalized with the flu, vaccinated patients spent an average of four fewer days in the hospital than unvaccinated patients. Some patients admitted to the hospital with acute coronary syndrome (a range of conditions associated with sudden, reduced blood flow to the heart) were randomly chosen to receive a flu vaccine before discharge. When these cases were reviewed, the group that received a flu vaccination cut their risk of having a major cardiac event by half. The meta-analysis of many studies shows that the protective effects of the flu vaccine were similar to the standard interventions, including statin therapy, antihypertensive medication, and smoking cessation.
According to Joshua J. Joseph, MD, MPH, FAHA, “The flu vaccine helps your body create antibodies to the viruses that cause influenza. Those antibodies then work to protect your body from infection if they encounter the flu. While it’s possible to still get sick, studies show that having had the flu vaccine reduces the severity of the illness.”
There are different flu vaccinations formulated for older adults. The American Heart Association (AHA) states that a standard flu shot seems to be just as protective as a “high-dose” flu shot in people with heart disease. A high-dose flu shot includes four components or a shot with four components plus more antigens to aid the immune system; both are designed for those aged 65 and older. The Centers for Disease Control and Prevention (CDC) reports some studies show newer vaccines (the high-dose inactivated vaccine, the adjuvanted inactivated vaccine, and recombinant influenza vaccine) might be more effective than standard-dose inactivated vaccines without an adjuvant.6 However, at this time, older adults are advised that there is no preference for one vaccine over another unless a person’s physician deems otherwise.
Risk Is Especially Great This Year
The AHA states that older adults and people with underlying risk factors for chronic illness, including heart disease, stroke, and diabetes, should receive a flu vaccine, especially “those 50 years old and older.” According to the CDC, those with one or more chronic risk factors who aren’t vaccinated are six times more likely to experience a heart attack if they are also battling the flu.8
Additionally, there are now further complications. “This flu season is unusual because last season we had relatively low influenza activity due to the measures we were taking to prevent COVID-19, things like masking and social distancing,” Joseph says. “Now, those measures have relaxed. We also have lower population immunity because of the low virus activity. Everyone getting their flu shot is an essential way we can keep the flu from spreading and claiming lives.” Joseph says the goal is to prevent a “twin-demic,” which refers to having high numbers of COVID-19 cases and influenza cases circulating at the same time. “It’s very important to keep this from happening,” he says, “so our health care systems can serve us best.”
There are tests to check for the presence of flu and COVID-19. Flu vaccination should be delayed for people who have a suspected or confirmed case of COVID-19. Those individuals can then receive the flu shot when they are no longer acutely ill or as advised by their doctor. In those without symptoms, the flu vaccination and COVID-19 vaccine may be given simultaneously.10
Sociodemographic Reasons Why People Don’t Get Flu Vaccination
Perception plays a part. In a Canadian Community Health Survey, people who judged their health as being poor were 21/2 times more likely to get a flu shot than were individuals who believed themselves to be in good health.13
Motivating health care staff about flu shots is vital as workers are already inundated by the pandemic. According to a 2007 study published in the British Journal of General Practice, the best motivation for older adults to get the flu shot is education and recommendation by health care professionals.14 Recent research confirms that providers can improve vaccine uptake through education. Providing patients with ideas about where to get safe, local access to flu shots is helpful if you cannot provide vaccination directly. Community outreach is effective, such as having a doctor, nurse, or other health care professional visit a senior center. Postcards, emails, ads on social media, and coupons for free vaccination are some ways to encourage older adults to get a flu shot. An article in the American Journal of Medicine suggested generating best-practice alerts in the chart to cue health care workers to remind patients to get vaccinated.15 Standing orders from the attending physician allow nurses, pharmacists, and other health care personnel to give flu shots to older patients who haven’t had them. Thus, they make the most of opportunities where patients may otherwise go unvaccinated.
Flu Represents an Ever-Changing Environment
However, since each season changes, it’s challenging to know which vaccine will always be effective in each season, so public health experts continue to gather data about newer vaccines and their effectiveness. Providers may consider recommending new vaccines as research becomes available. The CDC updates the information regularly beginning in mid-October at their “Weekly Flu Vaccination Dashboard.”
Health organizations around the globe encourage flu vaccination for people who live in the same household as older people and promote vaccination for caregivers and health care workers.15
A flu shot is not 100% effective, but may lessen the severity of illness. Although the pandemic has caused many to form new habits, older people should continue daily preventive habits as their first defense against the flu. For example, the CDC recommends that people stay home when they don’t feel well, wash hands often and wipe down surfaces, cover coughs and sneezes, practice good self-care (adequate rest, good diet, manage stress), and avoid close contact with people who are sick.
— Michele Deppe is a freelance writer based in South Carolina.
2. Yedlapati S, Khan S, Talluri S, et al. Effects of influenza vaccine on mortality and cardiovascular outcomes in patients with cardiovascular disease: a systematic review and meta-analysis. JAHA. 2021;10:e019636.
3. Flu shot linked to lower heart attack, stroke risk. Harvard Health Publishing website. https://www.health.harvard.edu/blog/flu-shot-linked-to-lower-heart-attack-stroke-risk-201310236795. Published October 23, 2013. Accessed November 17, 2021.
4. McCleskey E. Flu and heart disease: the surprising connection that should convince you to schedule your shot. Houston Methodist On Health Blog website. https://www.houstonmethodist.org/blog/articles/2021/oct/flu-and-heart-disease-the-surprising-connection-that-should-convince-you-to-schedule-your-shot/. Published October 8, 2021. Accessed November 17, 2021.
5. Udell J, Zawi R, Bhatt D, et al. Association between influenza vaccination and cardiovascular outcomes in high-risk patients: a meta-analysis. JAMA. 2013;310(16):1711-1720.
6. Fluzone high-dose seasonal influenza vaccine. Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/prevent/qa_fluzone.htm. Updated August 27, 2021. Accessed November 17, 2021.
7. Flu & people 65 years and older. Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/highrisk/65over.htm. Updated August 26, 2021. Accessed November 17, 2021.
8. Flu & people with heart disease and stroke. Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/highrisk/heartdisease.htm. Updated August 26, 2021. Accessed November 17, 2021.
9. Influenza and older adults. National Foundation for Infectious Disease website. https://www.nfid.org/infectious-diseases/influenza-and-older-adults/. Accessed November 17, 2021.
10. In light of pandemic, flu vaccinations more important than ever for people at highest risk. American Heart Association website. https://newsroom.heart.org/news/in-light-of-pandemic-flu-vaccinations-more-important-than-ever-for-people-at-highest-risk. Published November 9, 2020. Accessed November 17, 2021.
11. Estimates of influenza vaccination coverage among adults – United States, 2017-18 flu season. Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/fluvaxview/coverage-1718estimates.htm. Updated November 5, 2018. Accessed November 17, 2021.
12. Flu disparities among racial and ethnic minority groups. Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/highrisk/disparities-racial-ethnic-minority-groups.html. Updated November 9, 2021. Accessed November 17, 2021.
13. Gutherie J, Fisman D, Gardy J. Self-rated health and reasons for non-vaccination against seasonal influenza in Canadian adults with asthma. PLos One. 2017;12(2):e)172117.
14. Evans M, Prout H, Prior, Tapper-Jones L, Butler C. A qualitative study of lay beliefs about influenza immunization in older people. Br J Gen Pract. 2007;57(538):352-358.
15. Bhugra P, Grandhi G, Mszar R, et al. Determinants of influenza vaccine uptake in patients with cardiovascular disease and strategies for improvement. JAHA. 2021;10:3019671.
16. Vaccine effectiveness: how well do flu vaccines work? Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/vaccines-work/vaccineeffect.htm. Reviewed October 25, 2021. Accessed November 17, 2021.
17. How the CDC estimates the burden of seasonal influenza in the U.S. Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/about/burden/how-cdc-estimates.htm. Reviewed November 22, 2019. Accessed November 17, 2021.
Here’s a quick refresher to share with your geriatric patients about flu shots:
Timing. Getting vaccinated late is better than not at all. Ideally, adults 65 years and older should get a flu shot before the end of October. However, most older adults should not get vaccinated early (in the summer). Earlier vaccination isn’t recommended because the antibody response to the flu vaccine begins to decline over time. However, getting vaccinated later in the flu season, which ends in May, is always better than no flu shot. According to the Mayo Clinic, the flu shot takes about two weeks to reach its full effectiveness.3
Side Effects. Side effects from getting a flu vaccination are usually limited to soreness, swelling, or redness at the injection site. The vaccine does not cause the flu. According to the Centers for Disease Control and Prevention, flu shots have a long, established safety record.
Easy Access. Encourage older adults to seek the flu vaccine where they usually get their prescriptions filled. Doctors and some employers can provide vaccines as well. In addition, some facilities such as community health centers, churches, and federally funded programs offer the vaccine for free to older adults. Remind patients to wear a mask while being vaccinated this year.
Who Shouldn’t Get a Flu Shot? People with serious allergies, including those who have had a severe allergic reaction to flu shots in the past and those with a history of Guillain-Barré Syndrome, should not get the flu shot. Some people receive a nasal spray flu vaccine, but this is generally not recommended for people older than 49.4
Know the Difference. Although symptoms may be similar, according to the Centers for Disease Control and Prevention, we are not currently experiencing an influenza virus pandemic; there is only an ongoing pandemic with a “new” coronavirus. An influenza pandemic is a global outbreak of a new influenza A virus that is very different from the current and recently circulating flu viruses. Therefore, some patients should be informed that we’re vaccinating to prevent rising flu numbers during this time and that flu vaccines are altered every year to respond to prevalent viruses.5
2. McCleskey, Eden. Flu and heart disease: the surprising connection that should convince you to schedule your shot. Houston Methodist On Health Blog website. https://www.houstonmethodist.org/blog/articles/2021/oct/flu-and-heart-disease-the-surprising-connection-that-should-convince-you-to-schedule-your-shot/. Published October 8, 2021. Accessed November 17, 2021.
3. Flu shot: your best bet for avoiding influenza. Mayo Clinic website. https://www.mayoclinic.org/diseases-conditions/flu/in-depth/flu-shots/art-20048000. Published September 10, 2021. Accessed November 17, 2021.
4. Who should and who should not get a flu vaccine. Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/prevent/whoshouldvax.htm. Published August 24, 2021. Accessed November 17, 2021.
5. How is pandemic flu different from seasonal flu? Centers for Disease Control and Prevention website. https://www.cdc.gov/flu/pandemic-resources/basics/about.html. Updated May 7, 2019. Accessed November 17, 2021.