Shingles increases the risk of major adverse cardiovascular events (MACE), such as vascular dementia, heart attack, stroke, and death by nearly 25%, but people who received the shingles vaccine before developing shingles saw those risks drop, according to a large retrospective study.

I have previously discussed how the shingles vaccine helped reduce the risk of dementia and cardiovascular disease, and this study reinforces the evidence of the benefits of the vaccine beyond just preventing shingles, which is a huge benefit alone.

This article will review the new study and show just how dramatic the reduction in risks is.

Shingles and the vaccine

One of the complications of developing chickenpox, caused by the Varicella zoster virus (VZV), a herpesvirus, is that the body’s immune system does not destroy the virus. Once the symptoms of chickenpox disappear, the virus hides (it does not do this consciously; it’s a virus) in the dorsal root ganglion, a bundle of nerve fibers at the bottom of the spinal column. The virus stays there, hidden from the body’s immune system.

We are unsure why it does this, but it may be an evolutionary adaptation for survival until a later point in time, when it can reproduce and reinfect the victim.

Even though the body generated an immune response to the original zoster virus infection, several years or decades after the initial infection, the adaptive immune response against the virus wanes or disappears. Due to other unknown factors, possibly stress or other infections like COVID-19, the Varicella zoster virus “moves” along the nerve bundles and begins a secondary infection with much more serious consequences to the individual.

This second infection, called herpes zoster, is more commonly known as shingles. This infection usually occurs in adults older than 50, although it can happen at any time, occasionally even in young adults. 

Even though the same virus causes chickenpox and shingles, shingles was given a different name, herpes zoster, probably because it was originally thought to be caused by a similar, but unrelated virus. However, herpes zoster is not a formal name based on biological binomial nomenclature. We now know that the virus Varicella zoster causes both chickenpox and shingles.

Shingles is an entirely unpredictable disease. It appears at random points in time in response to unknown causes. Once shingles appear, they can be painful, depending on the location of the outbreak. It can cause blindness (from herpes zoster ophthalmicus), disfigurement of the infected area, permanent pain (postherpetic neuralgia), and other conditions.

Shingles can be treated with antiviral drugs, but only if the infection is recognized and treated within 24-72 hours, which means that the individual would have to seek out treatment rather quickly.

The initial symptoms may appear like acne or other skin conditions, which many people might ignore. After 72 hours, the disease has to run its painful and dangerous course. Post-herpetic neuralgia pain may last for weeks, months, or even years after the blisters have healed – this is not a trivial disease.

Furthermore, shingles is not a one-time event. Even if you develop shingles, it may return in months or years, so it is important to be vaccinated even if you have had shingles.

Almost all individuals in the US aged 50 years and older have been infected with VZV and are therefore at risk for shingles. There’s a growing body of evidence that herpes viruses, including VZV, may be linked to cognitive decline.

The only way to prevent a shingles infection is to boost the immune system with a vaccine against the zoster virus. The CDC recommends Shingrix (also known as the zoster vaccine, available in the USA), a relatively new, safe, and effective vaccine that prevents shingles. Shingrix has replaced the older shingles vaccine, Zostavax, because it is much more effective.

There is another way to prevent shingles — never get chickenpox in the first place. Of course, we have a vaccine for that, the chickenpox (or varicella) vaccine.

The CDC recommends the shingles vaccine for individuals 50 years or older. Additionally, the vaccine should also be given to individuals who are 19 years or older and have a compromised immune system. Other countries have different recommendations, so you should check the public health authorities for your home country.

So let’s be clear about a couple of things. First, you are only at risk for shingles if you contract chickenpox. Second, children who have received the chickenpox vaccine probably will not develop shingles as they age.

Research on shingles vaccination and cardiovascular events

In research presented at the IDWeek meeting (for infectious diseases), Ali Dehghani, DO, Case Western Reserve University, Cleveland, and colleagues examined more than 174,000 individuals, aged 50 or older.

Here are their key results:

• Those who developed a herpes zoster infection compared to people who hadn’t:
  • were 20% more likely to have a heart attack.
  • were 27% more likely to have a stroke.
  • were 30% more likely to die.
• Adults who received the shingles vaccine at ages ≥50 who later developed a first-time case of shingles:
  • had a 25% lower risk of heart attacks and strokes.
  • had a 27% lower risk of blood clots
  • had a 50% lower risk of vascular dementia

Summary

Although this study did not look at the change in risks of major adverse cardiovascular events in individuals who were vaccinated and did not develop shingles, this study provides overwhelming evidence that the shingles vaccine protects against dementia, heart attacks, and death.

As I keep saying, the greatest benefit of the shingles vaccine is that it is very effective in preventing shingles, a dangerous disease, especially for seniors. Preventing other conditions, like cardiovascular disease and dementia, is a bonus.

Even in groups of individuals who develop shingles after vaccination, the benefits remain mind-blowing.

With these studies, it is clear that if you have had chickenpox (or even think you’ve had it), you should protect yourself against shingles as soon as you are eligible.

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