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| From NFID Report |
#14,281
Two decades ago, a study looked at the rate of heart attacks in the United States, and found that Acute Myocardial Infarctions (AMIs) run as much 53% higher during the winter months than than during the summer.
Seasonal distribution of acute myocardial infarction in the second National Registry of Myocardial Infarction.
Spencer FA, Goldberg RJ, Becker RC, Gore JM.Cold weather combined with strenuous physical activity (like clearing snow from sidewalks) has often been blamed for this increase, but even in balmy Southern California, studies have shown a 33% increase in heart attacks over the holidays (see below).
When Throughout the Year Is Coronary Death Most Likely to Occur?
A 12-Year Population-Based Analysis of More Than 220 000 CasesThere are likely many factors involved, such as over-indulgence in food and alcohol, diminished activity levels, forgetting to take prescription medicines, and combined holiday stressors like shopping, running up debt, traveling, meal preparation, and the angst that comes from dysfunctional family gatherings are all likely contributors to this yearly spike.
Robert A. Kloner, MD, PhD; W. Kenneth Poole, PhD; Rebecca L. Perritt, MS
But increasingly influenza and other respiratory infections have been linked to a significant seasonal increase in heart attacks and strokes.
- Just last week, in PLoS One: Transient Depression of Myocardial Function After Influenza Virus Infection, we looked at a study that foundtransient myocardial function changes among a small group of influenza patients studied.
- In 2018's NEJM: Acute Myocardial Infarction After Laboratory-Confirmed Influenza Infection, we saw a study that found a `significant association ' between recent (lab confirmed) influenza infection and Myocardial Infarction.
- And in May 2017, in Int. Med. J.: Triggering Of Acute M.I. By Respiratory Infection we looked at research from the University of Sydney that found the risk of a heart attack is increased 17-fold in the week following a respiratory infection such as influenza or pneumonia.
Despite some less-than-stellar influenza Vaccine Efficiency (VE) numbers - particularly among those in the highest risk groups (65+) - we've seen some evidence that vaccination does reduce complications like heart attacks and strokes.
- In August of 2013 (see Study: Flu Vaccine May Reduce Heart Attack Risk), we looked at study out of Australia – published in the BMJ Journal Heart, that found compelling – but not exactly conclusive – evidence that flu shots may reduce the risk of heart attacks as much as 45%.
- In October of 2013 (see JAMA: Flu Vaccine and Cardiovascular Outcomes) we looked at a meta analysis that found among patients who had previously had a heart attack, the receipt of a flu vaccine was linked to a 55% reduction in having another major cardiac event in the next few months.
- In 2015, in UNSW: Flu Vaccine Provides Significant Protection Against Heart Attacks, we saw another study that found that if you are over 50 - getting the flu vaccine can cut your risk of a heart attack by up to 45%.
- Last year, a study appearing the American Heart Association's journal Circulation, found a substantial reduction in deaths among heart failure patients who received a yearly flu shot (see AHA: Study Shows Flu Shots Reduce Deaths From Heart Failure).
- Last January, in Chest: Flu Vaccine Reduces Severe Outcomes Among Hospitalized Patients With COPD, researchers found a lower mortality rate, less critical illness, and a 38% reduction in influenza-related hospitalizations in vaccinated vs unvaccinated individuals.
- Three weeks ago, in Flu Vaccine May Lower Stroke Risk in Elderly ICU Patients, we saw a study that found influenza vaccinated ICU survivors had a lower 1-year risk of stroke and a lower 1-year risk of death than unvaccinated survivors.
Flu vaccination linked with lower risk of death in patients with high blood pressure
01 Sep 2019
Topic(s): Hypertension Epidemiology
Paris, France – 1 Sept 2019: Influenza vaccination in patients with high blood pressure is associated with an 18% reduced risk of death during flu season, according to research presented today at ESC Congress 2019 together with the World Congress of Cardiology. (1)
Individually, these studies may not constitute a slam dunk, but when taken together there make a good case that the flu shot can do more than just prevent a nasty respiratory infection.“Given these results, it is my belief that all patients with high blood pressure should have an annual flu vaccination,” said first author Daniel Modin research associate of the University of Copenhagen, Denmark. “Vaccination is safe, cheap, readily available, and decreases influenza infection. On top of that, our study suggests that it could also protect against fatal heart attacks and strokes, and deaths from other causes.”According to previous research, the stress flu infection puts on the body may trigger heart attacks and strokes. Patients with hypertension (high blood pressure) are at raised risk of heart attack and stroke. By stopping flu infection, vaccination could also protect against cardiovascular events, but until now this had not been investigated.
The study used Danish nationwide healthcare registers to identify 608,452 patients aged 18 to 100 years with hypertension during nine consecutive influenza seasons (2007 to 2016). The researchers determined how many patients had received a flu vaccine prior to each season. They then followed patients over each season and tracked how many died. In particular, they recorded death from all causes, death from any cardiovascular cause, and death from heart attack or stroke.
Finally, they analysed the association between receiving a vaccine prior to flu season and the risk of death during flu season. The analysis controlled for patient characteristics that could impact the likelihood of dying such as age, comorbidities, medications, and socioeconomic status.
After adjusting for patient differences, in a given influenza season, vaccination was associated with an 18% relative reduction in the risk of dying from all causes, a 16% relative reduction in the risk of dying from any cardiovascular cause, and a 10% relative reduction in the risk of dying from heart attack or stroke.
Mr Modin said: “We show that influenza vaccination may improve cardiovascular outcomes in patients with hypertension. During the nine flu seasons we studied, vaccine coverage ranged from 26% to 36%, meaning that many patients with high blood pressure were not vaccinated. If you have high blood pressure, it would be worth discussing vaccination with your doctor.”Regarding how flu and cardiovascular disease might be connected, Mr Modin noted that when the influenza virus infects the body it triggers a strong immune reaction and subsequent inflammation. These responses fight the infection and clear the virus from the body but may increase the risk of having a heart attack or stroke.
He said: “Heart attacks and strokes are caused by the rupture of atherosclerotic plaques in the arteries leading to the heart or the brain. After a rupture, a blood clot forms and cuts off the blood supply. It is thought that the high levels of acute inflammation induced by influenza infection reduce the stability of plaques and make them more likely to rupture.”ENDS
And even when it doesn't prevent flu infection, it may help reduce the severity of one's illness (see CMAJ Research: Repeated Flu Vaccinations Reduce Severity of Illness In Elderly).I view getting a yearly flu shot like always wearing a seat belt in an automobile. It doesn't guarantee a good outcome in a wreck, but it sure increases your odds of walking away.
And despite the anti-vaccine rhetoric on the internet, flu vaccines have an excellent (albeit, not perfect) safety record.All reasons why I'll be rolling up my sleeve again this fall, and I urge others to look at the evidence, and hopefully decide to do the same.
