The benefits of avoiding shingles through vaccines are piling up. New research this week found a link between vaccination of shingles and a reduced risk of heart attack and stroke.
Researchers at South Korea's Kyung Hee University published the study in the European Journal of Heart on Monday. They studied the medical records of more than one million Korean residents and found that people with shingles were significantly less likely to develop cardiovascular disease than those without vaccination. These findings are the latest to show that shingles are worse than they currently think for our health.
“This shows that the vaccine not only prevents the shingles themselves from providing protection, but also provides potential benefits for heart health,” research researcher Sooji Lee told Gizmodo in an email.
Shingles are caused by the varicella zoster virus, the same bacteria that causes chickenpox in children. Although chickenpox is usually transient, if unpleasant, the virus can survive the initial immune response and stay dormant in our bodies for decades. When our immune system becomes weaker, it is often due to age that the virus reactivates and triggers a new infection we call shingles.
The second round is usually worse, causing symptoms such as pain and rash lasting for weeks. Sometimes, shingles can even leave lingering, potential lifelong nerve pain.
Although shingles are bad, ongoing research suggests that it may also increase the risk of future health problems. For example, several studies have linked shingles to the greater risks of Alzheimer’s disease and dementia, and in contrast, lower risk of dementia is associated with vaccination for shingles. Some studies have also shown that shingles can cause heart complications after infection. However, according to the researchers, there is no extensive research on whether these problems can be prevented.
In Korea, health care is largely covered by a single payer, publicly funded system. The system means scientists can use identifying (anonymous) data to study the health of South Korea’s population more easily. Researchers cross-referenced different data sources to track vaccination status and cardiovascular health of South Korean residents aged 50 and older, which began in 2012 when the vaccine was first launched in the country.
They eventually found that shingles vaccination was 23% lower with any cardiovascular disease, as well as a 26% lower risk of large cardiovascular events (heart attacks and strokes) and a 26% lower risk of heart failure. The decline in cardiovascular disease is the strongest in the first two to three years after vaccination, but can still be seen eight years later. Among men, protection from vaccination also appears to be stronger, suffering from poorer health conditions and people living in rural or low-income communities.
“Because our research was conducted in large populations, these findings may be widely applicable,” Lee said.
Such studies are observational, meaning they cannot explicitly demonstrate the causal relationship between the two factors, showing only the correlation (in this case, between shingles vaccination and decreased heart disease). But the authors point out that shingles can cause inflammation, blood clots and general vascular damage, which are all known risk factors for cardiovascular disease. They also speculate that nerve damage caused by shingles may interfere with our heart rhythm, which may cause problems such as cardiac arrest.
Another consideration is that the researchers have only studied the potential effects of the old shingles vaccine Zostavax, which uses a weak version of the virus to generate immunity. The vaccine is largely replaced by a different type of shingles vaccine called Shingrix, which uses only proteins from the virus. This newer vaccine is more effective in preventing shingles, and some studies have shown that it can also provide greater protection against dementia.
Lee said her team is now planning to study whether Shingrix can provide the same level of protection, or even better.
Having said that, shingles can be very unpleasant, so getting vaccinated is already worth it. If you’re lucky, vaccines may also boost our brain and heart health.
