Why we vaccinate-flu vaccine reduces cardiovascular risks

senior-flu-vaccineIn addition to preventing the infection, the flu vaccination may have a more important benefit for those who get the shot. A new systematic review, published this week in the Journal of the American Medical Association (JAMA), found that individuals vaccinated against the flu had a significantly lower risk of a major cardiovascular events, such as a heart attack or stroke, compared with those who received no flu vaccine.

In the meta-review, researchers from the University of Toronto analyzed five published studies and one unpublished study. They then rolled-up the data to investigate the connection between those who were vaccinated against the flu and various cardiovascular events. Altogether, the studies included approximately 6000 patients. Moreover, the patients had an average age of 67, while about one-third had a medical history of heart disease.

The results were dramatic–individuals who were vaccinated against the flu had a 2.9% risk of having a major cardiovascular even with the next eight months. The risk for those who were not vaccinated (or received a placebo) increased by 150% to 4.7%, a statistically significant difference.

Just to be clear, the study did not show that getting the flu virus caused the development of cardiovascular disease. However, patients with diagnosed cardiovascular disease (or who have had cardiovascular events, such as myocardial infarction) are at a significantly greater risk of another one if they catch the flu. As the authors state, “the greatest treatment effect was seen among the highest-risk patients with more active coronary disease.”

According to the study, less than 50% of people under the age of 65 with high-risk conditions (such as cardiovascular disease) receive the flu vaccine, which puts them at risk of complications like heart attack and stroke. Older individuals, who often have existing health problems, appear to be more likely to be vaccinated, although up to one third still skip their annual flu shot.

One last point–getting the vaccine, whether the patient has underlying cardiovascular disease or not, does not increase the risk of any cardiovascular effects.

We’ve all heard the excuses and myths about the flu vaccines. They just aren’t trueNo, they really really really aren’t true. By the way, Mark Crislip, MD, thinks those of you who make up whiny excuses for not getting the flu vaccine are dumbasses. His words, but quite apropos.

So, if you have had cardiovascular disease, or are at risk from it (like those who have type 1 or 2 diabetes), then get a flu vaccination no matter what your age is. If you have any other risk factors, like being under the age of 5, pregnant, or other important chronic conditions, get a flu immunization. If you’re a healthy adult, and you’re going to visit your parents or grandparents who could catch the flu from you, get vaccinated, even if they’ve been vaccinated (because there is some small chance that the vaccine didn’t give them full immunity). Just get vaccinated for the flu.

The clinical value of preventing the flu is huge. The mythical risks of getting the vaccine are invisible.

If you need to search for accurate information and evidence about vaccines try the Science-based Vaccine Search Engine.

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Vaccines save lives–even more evidence

Vaccines-save-lives;-fear-endangers-them.-It's-a-simple-message-parents-need-to-keep-hearing.One of my favorite tropes (of so many) of the vaccine denier gang is that vaccines are not effective, thereby implying that the limited usefulness is not worth the risks of vaccines, real or imagined. But the fact is vaccines do save lives in measurable and sometimes fascinating ways. Two peer reviewed papers, recently published, provided clear evidence of some of the ways vaccines directly save lives.

The first article analyzed the relationship between flu vaccines and reduction of cardiovascular events; while the second one examined how vaccines might reduce morbidity and mortality from pneumococcal meningitis.

Let’s start with the flu vaccine, which has a high safety profile and most people receive for the obvious reasons–flu prevention. However, we are aware of other benefits of the flu shot, including providing somewhat better outcomes during pregnancy. In an article published on 21 August 2013 examined a previously suspected, but not firmly established, benefit of the flu vaccine was examined. This study found that the risk of getting a heart attack was about 50% less amongst patients who were vaccinated against the flu compared to a group that was not.

Now, the study does not show that the flu vaccine has some miraculous anti-heart attack component, it might reduce the risk of catching the flu, or possibly reducing the severity of the infection, which reduces the risk of having a heart attack. In fact, the study’s original hypothesis was that catching the flu might actually increase the risk of a cardiovascular event, specifically a heart attack.

Furthermore, the researchers observed that the flu vaccine reduced heart attack risk even when the vaccine’s effectiveness was shown to be not very high. This conclusion itself debunks one of the huge myths of the antivaccination crowd (which is essentially that if it’s not 100% effective then we must conclude that it’s 0% effective, an application of the Nirvana logical fallacy); sometimes even when a vaccine isn’t completely effective, it still has some net positive effects. Continue reading “Vaccines save lives–even more evidence”

Vitamin D and high blood pressure–probably ineffective

supplementsVitamin D is a group of fat-soluble steroid-like biochemicals that have one known responsibility in human health–enhancing intestinal absorption of calcium and phosphate, minerals which are necessary for bone development and bone health. In humans, the most important D vitamins are vitamin D3 and vitamin D2, both of which can be ingested from dietary sources, including fishes, milk products, and many other foods. However, the body can synthesize vitamin D’s in the skin when exposure to sunlight is adequate. Because humans can produce their own vitamin D, it is not strictly considered an essential dietary vitamin, which are vitamins that cannot be synthesized in sufficient quantities by an organism, and must be obtained from its diet.

Even though supplementation is necessary for people who aren’t receiving adequate levels of vitamin D through either sun exposure or diet, excessive intake of the vitamin causes a condition called hypervitaminosis D. Excessive vitamin D can lead to acute problems, like excess thirst or increased urination, but over a long-term can lead to heart disease and other chronic conditions.  

Despite the understanding that vitamin D has only one real function, regulation of calcium and phosphate uptake, that hasn’t stopped the junk medicine pushers from making all sorts of claims about its usefulness in human health. In fact, recent studies have shown that vitamin D doesn’t reduce the risk of breast cancer, one of the more popular myths about the vitamin. Continue reading “Vitamin D and high blood pressure–probably ineffective”

Multivitamins–big money, no effect on cardiovascular disease

A few months ago, I wrote about the role of supplements, mainly vitamins and other nutrients, in preventing cancer. Conclusion: they didn’t. To quote Martinez et al., who published a review of dietary supplements and vitamins in cancer prevention

Nutritional supplementation is now a multibillion-dollar industry, and about half of all US adults take supplements. Supplement use is fueled in part by the belief that nutritional supplements can ward off chronic disease, including cancer, although several expert committees and organizations have concluded that there is little to no scientific evidence that supplements reduce cancer risk. To the contrary, there is now evidence that high doses of some supplements increase cancer risk. Despite this evidence, marketing claims by the supplement industry continue to imply anticancer benefits. Insufficient government regulation of the marketing of dietary supplement products may continue to result in unsound advice to consumers. Both the scientific community and government regulators need to provide clear guidance to the public about the use of dietary supplements to lower cancer risk. 

All those expensive supplements, most of which have broad and unproven claims made about them, do precious little for cancer. And some actually increase the risk of certain types of cancer. Continue reading “Multivitamins–big money, no effect on cardiovascular disease”

Flu vaccination helpful to patients with implantable cardiac defibrillators

A couple of days ago I reported that the flu vaccination not only prevents the flu itself, but it may also reduce risk of certain types of heart disease and death from cardiovascular events. In another study presented at the Canadian Cardiovascular Congress meeting in Toronto, the authors stated that the flu vaccination may have a critical benefit to patients who have implantable cardiac defibrillators (ICD), a small battery-powered device that automatically detects cardiac arrhythmias, then corrects it by delivering an electrical shock that can revert ventricular fibrillation, and that has been extended to include both atrial and ventricular arrhythmias. 

According to study author Dr. Ramanan Kumareswaran, physicians have known that patients tend to need more ICD shocks during flu season, and wanted to investigate ways of reducing this need to rely on the device.

The study surveyed 229 patients who had come in for appointments related to their ICD care from September through November 2011. Of those patients, 179 (78%) reported that they had received the influenza vaccination in the previous year. Patients who received the influenza vaccine were older than those who did not (70.8 vs. 64.8 years, P=0.0005). Finally, there was no difference in the prevalence of coronary artery disease, diabetes, renal disease, and prior stroke in patients the vaccinated and un vaccinated patients.

Some of the results of the survey were:

  • Patients who received the flu vaccine were more likely to reject statements such as, “The Flu shot is not effective” and “The Flu shot will make me sick” compared to individuals not receiving the influenza vaccine.
  • Vaccinated individuals also planned to obtain the influenza vaccine in the upcoming year. 
  • Thirty nine (17.0%) individuals in the overall cohort received at least one ICD therapy during the two pre-defined periods – 10.6% who received the influenza vaccine received at least 1 ICD therapy during influenza season compared to 13.7% who did NOT receive the influenza vaccine (P=NS). 
  • About 13.7% of the unvaccinated patients experienced at least one ICD therapy (meaning that the ICD device had to adjust the heart rate) during the flu season compared to the 10.6% of patients who were vaccinated. This wasn’t a significant difference. However, the average number of ICD therapies per person during influenza season was greater in individuals not receiving the influenza vaccination (0.45 therapies) compared to individuals who did receive the influenza (0.14 therapies).

“What is interesting is that if this is consistent over time, it could be of significant benefit to our patient population who already have compromised survival to start with,” wrote Dr. Sheldon Singh, one of the study’s authors.

The authors concluded:

A large proportion of patients with ICDs receive the influenza vaccine. Receipt of the influenza vaccine may be associated with a reduction in ICD therapies during influenza season.

Now, as I’ve said with the other study, from the same Canadian Cardiovascular Congress meeting, that showed that a link between getting the flu vaccination and reduced cardiovascular events, these studies are not peer reviewed. They aren’t published yet in journals. They haven’t been repeated by other researchers. But the study seems to be sound, and it is a very sound argument for getting the flu vaccination if you have serious cardiovascular issues.

And don’t listen to those myths about the flu vaccine, they just aren’t true. No, they aren’t true.

Vaccines save lives.

Use the Science-based Vaccine Search Engine.

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Flu vaccination may reduce risk of heart disease and death

In addition to preventing the disease, the flu vaccination may have a more important benefit to those who get the shot. Dr. Jacob Udell, a cardiologist at Women’s College Hospital and the University of Toronto, looked at published clinical trials on flu vaccinations, dating back to the 1960s, examining the vaccine’s effect on cardiovascular events. Dr. Udell presented his meta-review results at the 2012 Canadian Cardiovascular Congress on October 28 2012.

The combined studies examined a total of 3227 patients, with an equal split between patients with and without heart disease. Half of the patients were randomly assigned to receive flu vaccine, and those that did not received a placebo. Four randomized controlled trials of moderate quality conducted between 1994-2008 met inclusion criteria. Here are some of the most important results:

  • An approximate 50 per cent reduction in the risk of a major cardiac event (heart attack, stroke, or cardiac death) compared with placebo after one year of follow-up. 
  • A similar trend was seen for the flu vaccine reducing death from any cause (approximately 40 per cent). 
  • The influenza vaccine reduced cardiovascular events and cardiovascular death in people with or without heart disease. 
The study concluded:
Influenza vaccine reduced non-fatal CV events and may reduce sudden CV death in patients with and without CVD. However, the very low number of observed CV events and important design limitations among these RCTs strongly limit their validity and make it challenging to draw a definitive conclusion. A large, adequately powered, international multicenter RCT testing the efficacy of influenza vaccine to reduce incident and recurrent CV events is prudent to confirm these findings.

According to a report by Jennifer Nelson at NBC News, “The flu vaccine could be an important way to maintain heart health and ward off strokes and heart attacks, the researchers said.” Nelson also quoted Dr. Udell as proclaiming that “perhaps that the flu vaccine is a heart vaccine.” Well, maybe that’s overstating the case, but who knows.

But why would the flu vaccine reduce cardiovascular events? Nelson’s report suggested a couple of very plausible reasons:

  1. “Udell said it may be that when people develop heart disease, some factor  ‘tips them over the edge,’ such as plaque clogging arteries, or lower levels of oxygen as a result of the flu.” This is entirely possible, since those with atherosclerosis do have reduced blood flow to heart muscle. And the flu, being much more dangerous than most people believe, could just push someone over the line from having just enough oxygen for their heart muscle, to not enough.
  2. “Dr. Sarah Samaan, a cardiologist and director of the Women’s Cardiovascular Institute at Baylor Heart Hospital in Plano, Texas, said the key to the link may be in reducing inflammation. When someone gets the flu, blood levels of inflammatory substances rise, and inflammation of the blood vessels can trigger heart attacks. ‘This happens because inflammation can make cholesterol plaques in the blood vessels unstable,’ Samaan explained. Unstable plaques are more likely to develop tiny cracks, which can cause blood clots to form. Such clots can block blood flow within arteries, causing a heart attack (if the blood vessel supplies the heart) or a stroke (if the artery feeds the brain), she said.” Again, entirely plausible.

Now, a couple of caveats about this study. First, it’s presented at a conference. Second, it’s not peer-reviewed. I’ll assume that it’s good work, but until it’s peer-reviewed and published in a great journal, it’s at the level of highly provocative. And it’s intensely interesting. But the great thing about meta-reviews is that they are easily repeated, and easily criticized if there’s a problem with the statistical analysis, so in light of that, I have high confidence in the quality of these results.

The 50% reduction in cardiovascular events is both clinically relevant, and may be higher than what will be seen in future randomized trials. But even if it’s 40%, 30%, or even 10%, that’s an amazing benefit of the flu vaccine for individuals at risk for cardiovascular events. The thing is that although a lot of people know that they are at risk, they have diabetes or are overweight, many people are unaware of their cardiovascular risks. They may have untreated hypertension. Or atrial fibrillations. Or any number of diseases where the risks of cardiovascular events are high, and can reduce the risk by a significant amount just by a simple and safe flu vaccination. And don’t listen to those myths about the flu vaccine, they just aren’t true. No, they aren’t true.

Vaccines save lives. And they might keep you from getting a heart attack!

Use the Science-based Vaccine Search Engine.

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Eggs and your arteries–yolk or no yolk

Here we go again. The popular press gets ahold of a scientific study, misinterprets it, and runs a scary story. Of course, it’s much worse if the scientific study published in a respected journal seems to also misinterpret the study. As I mentioned before, a true skeptic needs to critically analyze whatever is written in the press by going to the original study whenever possible; but what happens if that study requires some critical analysis? Well, I never said it was easy. If you want easy, denialism is really easy!

So back to the eggs. All across the news during the past week or so, you probably saw a story that eating egg yolks cause arteriosclerosis, a chronic condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol. Some people may have already believed that anecdotally, but a new article published in AtherosclerosisEgg yolk consumption and carotid plaque, concluded that, 

Our findings suggest that regular consumption of egg yolk should be avoided by persons at risk of cardiovascular disease. This hypothesis should be tested in a prospective study with more detailed information about diet, and other possible confounders such as exercise and waist circumference. Continue reading “Eggs and your arteries–yolk or no yolk”

Stem cell treatments for heart attacks

Acute myocardial infarctions (AMI), commonly known as heart attacks, are responsible for about 12.6% of deaths worldwide, according to The World Health Report 2004 – Changing History.  In the United States, about 16.6% of those who have heart attacks die within 30 days of the attack.  Outside of AIDS and a few infectious diseases, AMI is the biggest killer of adults.

An AMI is essentially caused by a blockage of the coronary arteries which leads to cellular damage of some of the heart muscle (myocardium).  This prognosis can be minor to deadly, depending on a lot of issues such as other cardiovascular risk profile (diabetes, peripheral vascular disease, smoking and others), quality of treatment, and severity of the tissue damage.  Over the past few years, treatments have improved the outlook for AMI sufferers, but the risk of a subsequent heart attacks and mortality rates are still high. Continue reading “Stem cell treatments for heart attacks”