Vaccine surprising side effects that may improve long-term health

I am currently making an appointment for a shingles vaccination. I had shingles in university and still carry the scars so I really don’t want to risk it happening again. But I also mean the fact that the benefits of the shingles vaccine are not limited to shingles prevention. And that’s not unusual. We’re finding that many vaccines have benefits that go far beyond protection against a single virus or bacteria—facts that aren’t nearly as well known as they should be.

Let’s start with shingles. A study of more than a million people last year reported that those who received the Zostavax shingles vaccine were 26 percent less likely to die of heart disease or have a stroke, heart attack or heart failure an average of six years after the shot — a massive risk reduction for such a simple, cheap and easy procedure.

What’s more, people given the newer shingles vaccine, called Shingrix, were 17 times less likely to develop dementia over the next six years compared to those given Zostavax. Since several studies have shown that Zostavax also reduces the risk of dementia, the overall risk reduction with Shingrix should be even greater. Several other vaccines, including those that protect against influenza and tuberculosis, it also appears to reduce the risk of dementia.

In the US and Australia, shingles vaccination is recommended for those over 50 or adults with weakened immune systems. If you do not fall into this last category in the UK, it is only available through public healthcare for people aged 70 to 79. I don’t want to wait that long so I’ll have to go private.

Shingles is caused by the varicella zoster virus, which causes chickenpox when it first infects us in childhood, and then lies dormant in nerve cells and causes shingles when it reactivates. So it’s possible that vaccinating children against chicken pox may have some benefits later in life, although I haven’t found any studies that look at this.

Influenza vaccines also have cardiovascular benefits. For example, an analysis combining data from more than 9,000 people involved in six studies found that those who received the flu shot had a 34 percent lower risk of heart attack or stroke in the next year. The benefit was even greater in people with a recent history of heart problems.

New vaccines against RSV, or respiratory syncytial virus, also appear to help prevent heart problems. ON studies involving about 130,000 people over the age of 60 found that those who had one type of RSV vaccine were less likely to be hospitalized for heart or lung problems than those who were unvaccinated.

Then there are covid-19 mRNA vaccines. Combined with immunotherapy, they have been shown to boost the immune response to tumors and prolong people’s lives.

I could go on to list examples, but instead let’s look at why so many vaccines have these broader benefits. We don’t know the exact mechanisms for sure, but it’s not that surprising that they do.

Viruses can cause permanent physical damage to the body, and the immune response to them can also damage tissues. So-called cytokine storms, in which the body overreacts and releases too many immune-stimulating signals, are often what kill people with infections such as the flu or covid-19, and there is growing evidence that multiple sclerosis is the result of an immune response to the Epstein-Barr virus.

Many viruses also target our immune system in various ways to help it escape, thereby weakening our defenses. HIV takes this strategy to an extreme and kills it completely.

There are also viruses that we cannot get rid of once they infect us, such as the varicella zoster virus. Some, such as the human papillomavirus (HPV), even genetically modify our cells by inserting their genome into ours – which is why HPV causes cancer.

The thing is, even viral infections that we tend to think of as harmless, like the flu in young people, can have long-term effects that aren’t always overtly associated with those infections. Long covid studies have helped raise awareness of this – and the benefits of vaccines in reducing the risk of lasting damage.

There is an idea in some circles that “natural immunity” against disease is little better than vaccination. It’s nonsense for all the reasons above and more, and measles is a great example of that.

Measles vaccines have reduced deaths from the disease from more than 2 million annually before 1980 to less than 100,000 in 2024. They also had an unexpected effect reducing the number of children dying from other infectious diseases.

Why? Part of the answer is that measles kills some immune cells, leaving children more vulnerable to a wide range of infections for many years. But measles vaccines also appear to train the immune system in ways that increase its broader effectiveness. This training effect is so beneficial that it has even been suggested we should give children measles vaccine even if measles is cleared.

Of course, it would be too good to be true if all vaccines trained our immune systems in this way. There is evidence that several vaccines have the opposite effect. But that doesn’t mean they don’t still save lives overall.

As always with vaccines, the key question is whether getting vaccinated is better than not getting vaccinated. In order to make an informed decision, you need to balance the risks of infection versus vaccination and also consider the wider benefits of the vaccine. All too often we focus exclusively on the very rare or entirely imaginary side effects of vaccines.

I have no doubts about what will make me better. I get the shingles vaccine and the flu shot every year and the RSV vaccine when offered, at least.

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