Influenza (commonly referred to as flu) is an infectious illness caused by the influenza virus. Each season, many people are affected by flu that spreads through the air. Vaccination is available for flu, and it continues to be the best way of preventing its incidence.1
Recent studies have shown that taking a flu shot can reduce cardiac events in people with hypertension.2 Taking flu shots also reduces the risk of a stroke.3 This article will be focussing on how people taking flu shots may be at a reduced risk of death related to hypertension.
What are the symptoms of the flu?
Flu may cause mild illness; however, it may sometimes become severe and even lead to death.1 Some of the symptoms of flu are:1
- Chills and fever
- Cough and cold
- Runny or stuffy nose
- Soreness in the throat
- Muscle pain
- In some cases, diarrhoea and vomiting
The strains of flu virus undergo a constant change; hence, it is advisable to get a flu shot every year as a new vaccine is developed every year.4
What is the association between flu and heart disease?
Evidence points to the fact that of the people hospitalised for flu in a particular year, almost half had heart problems and that flu is likely to be associated with the risk of heart attacks and stroke or other conditions such as hypertensive heart disease (a condition caused by high blood pressure), heart failure and arrhythmias (irregular heartbeat).5 Studies have also shown that influenza-like illnesses are associated with fatal and non-fatal heart-related events.6 Although the reasons for the association between influenza and heart-related events are not completely clear, scientists have put forth the following reasons after extensive research:6
- Rupture of a plaque that accumulates in the arteries of the heart
- Heart failure due to fluid overload
- Myocarditis (inflammation of the heart muscles)
- Arrhythmias (irregular heartbeats)
Evidence points out that the stress encountered by the heart due to influenza can trigger heart attacks and strokes.2
How are flu shots associated with lowering the risk of death due to hypertension?
Patients who have been diagnosed with high blood pressure or hypertension are at a greater risk of heart diseases such as heart attack and stroke.2 In clinical trials conducted on people with heart diseases, those who took flu shots demonstrated less cardiovascular events within one year after the administration of flu shots as compared to those who were treated with a placebo.6 According to the trial, flu shots were associated with reducing cardiovascular events.6 Some studies conducted on animals have demonstrated that the immune response to the vaccination has a stabilising effect on the plaque, thereby avoiding its rupture and subsequent stroke.7 Researchers noted that people who took a flu vaccine were 16% less likely to die from a cardiovascular problem and 10% less likely to die from stroke or heart attack.8
Evidence gathered from research studies demonstrates that the inflammation caused by flu can cause a heart attack or stroke, especially in people with high blood pressure. Recent studies have proven that the administration of flu shots every year may lower the number of deaths by preventing a cardiac event such as a stroke or heart attack.2,8
Your health is in your hands! Get a flu shot every year; protect yourself from flu and help protect your heart from heart-related risks as well.
- Centers for Disease Control and Prevention. Key facts about influenza (flu) [Internet]. [updated 2019 Sep 13; cited 2019 Dec 11]. Available from: https://www.cdc.gov/flu/about/keyfacts.htm.
- European Society of Cardiology. Flu vaccination linked with lower risk of death in patients with high blood pressure [Internet]. [updated 2019 Sep 1; cited 2019 Dec 11]. Available from: https://www.escardio.org/The-ESC/Press-Office/Press-releases/Flu-vaccination-linked-with-lower-risk-of-death-in-patients-with-high-blood-pressure.
- NHS. Flu jab may cut stroke risk by a quarter [Internet]. [updated 2014 Feb 21; cited 2019 Dec 11]. Available from: https://www.nhs.uk/news/neurology/flu-jab-may-cut-stroke-risk-by-a-quarter/.
- NHS. Flu vaccine overview [Internet]. [updated 2019 Jul 16; cited 2019 Dec 11]. Available from: https://www.nhs.uk/conditions/vaccinations/flu-influenza-vaccine/.
- Centers for Disease Control and Prevention. Flu and heart disease and stroke. [Internet]. [updated 2019 Oct 23; cited 2019 Dec 11]. Available from: https://www.cdc.gov/flu/highrisk/heartdisease.htm.
- Udell JA, Zawi R, Bhatt DL, Keshtkar-Jahromi M, Gaughran F, Phrommintikul A, et al. Association between influenza vaccination and cardiovascular outcomes in high-risk patients: a meta-analysis. JAMA. 2013 Oct 23;310(16):1711-20. doi: 10.1001/jama.2013.279206.
- Lee KR, Bae JH, Hwang IC, Kim KK, Suh HS, Ko KD. Effect of influenza vaccination on risk of stroke: a systematic review and meta-analysis. Neuroepidemiology. 2017;48(3-4):103-110. doi: 10.1159/000478017.
- Harvard Health Publishing. Harvard Medical School. Flu shot may lower risk of early death in people with high blood pressure [Internet]. [updated 2019 Dec; cited 2019 Dec 11]. Available from: https://www.health.harvard.edu/heart-health/flu-shot-may-lower-risk-of-early-death-in-people-with-high-blood-pressure.