Connecting the Dots: Chicken Pox, Varicella Vaccine and Shingles
Today’s guest post from Dr. Lara Zibners addresses a follow-up question we received on our Vaccinate Your Baby Facebook page in response to a previous post about the varicella (chicken pox) vaccine.
“How likely is it that my older 2 kids (who got wild pox and weren’t vaccinated) will get shingles later?”
Boy, do I love a follow-up question! It means someone out there actually took the time to read my words, contemplate their meaning, and push the issue further. So let’s take the question in parts A & B: (A) what is the risk of developing shingles over one’s lifetime? and (B) is the risk different if an individual has “wild-type” chicken pox versus the varicella vaccine?
First off, let’s start by stating one unarguable fact: shingles sucks. Sorry, there’s no other way to describe it. Burning pain followed by nasty little blisters which are confined to what we call a “dermatome.” A dermatome is an area of the skin that is supplied by a single spinal nerve. In other words, the area of the spine called “T4” (for thoracic nerve #4) provides sensation to the nipple line and “T10” is the level of the belly button. Does that make sense? It may help if I tell you that as a first year medical student I dressed up as “Dermatome Man” by spray painting a sweat suit in stripes of pink, yellow and blue and writing the corresponding dermatome in each area. If that doesn’t help, then it just confirmed for you that I’m a dork. Fine. Moving on.
When a body encounters the varicella virus, either via wild-type chicken pox infection or the vaccine, the virus can basically go for a long snooze in one of these spinal nerves. If it wakes up, it causes shingles, also known as herpes zoster. Complications include zoster of the eyes (causing scarring), infection of the blisters, or infection of other organs of the body including the brain, liver or lungs. As if zoster itself wasn’t miserable enough. What’s even worse is that some people go on to develop a condition called “post herpetic neuralgia.” This is where the blisters have gone away (in about 1-2 weeks) but the burning painful sensation remains, in some cases for years. The pain can be so terrible and debilitating that it has even driven some poor souls to suicide. If that isn’t the definition of “sucks,” I don’t know what is.
So now to the heart of the question. What is the risk that a child will develop shingles at some point in his life? The answer partly depends on how long he lives. As we age, along with our knees and eyesight, our immune systems begin to show signs of wear and tear. This means a greater chance that the varicella zoster can “wake up.” About 50% of people over the age of 85 will have had an episode of shingles. Other people at risk include those with abnormal immune systems, such as children on chemotherapy for cancer.
But there is some good news. Lots of good news, actually. First and foremost is that while scientists are still researching this exact question, it appears that the risk of shingles may be lower for people who have received the varicella vaccine as opposed to having suffered through “wild-type” chicken pox. Of course, that news is only good if your child had the vaccine, isn’t it? Well, don’t lose hope. Because there is more good news. In the form of another vaccine.
Yep, it is now part of our routine immunization recommendations for adults 60 years and older to receive a dose of the zoster vaccine. The zoster vaccine is basically a ramped up version of the varicella vaccine, with at least 14 times the concentration of the live-attenuated virus. That’s enough to wake up the immune system memory and keep that sleeping varicella quiet. While the vaccine isn’t perfect, resulting in about a 50% decrease in the risk of shingles, it is very good at preventing the complications. In a study of over 38,000 adults, there was a significant decrease in duration and severity of the disease and almost a 70% decrease in the risk of post-herpetic neuralgia.
So there you have it. There is an argument that ongoing lifetime exposure to children with “natural” chicken pox will prevent shingles. And that we’ve tinkered with this system by immunizing against varicella in the first place. Which is technically true. Repeated exposure will keep the old immune system more awake and charged up, better prepared to beat down that pesky varicella. But the vaccine does the same thing. And vaccinating against both means a lower risk of severe complications from chicken pox and a much lower risk of severe complications from zoster. Which is worth celebrating, eh?
For more information on the zoster vaccine and shingles, check out these links.
In addition to being painful, there are instances when shingles can have a severe impact on people. This video from PKIDs on the Shot By Shot gallery is just one more reason you’ll want to do what you can to avoid getting shingles.