For virtually all adults in the United States, the chickenpox is little more than an unpleasant childhood rite of passage. After a scratchy, feverish and miserable week or so, the illness usually fades to a memory, and, perhaps a few tiny, unfortunate scars.
But for roughly one in four to one in five people over their lifetime, the chickenpox virus recurs as shingles, a painful, blistering rash that usually attacks one side of the body. About 1 million American adults annually suffer from shingles.
The culprit behind both shingles and chickenpox is the varicella-zoster virus, or VZV. It's a member of the herpesviruses family that causes cold sores, fever blisters, mononucleosis and genital herpes. These viruses share a common capacity to hide in the nervous system after initial infection, then to cruise down nerve cell fibers and reignite inflammation. Recurring cold sores are the most common example.
Shingles, also known as herpes zoster, often starts as pain, burning, numbness or tingling, followed by an itchy, often excruciating red rash a few days later. Fluid-filled blisters erupt, split open and crust over. Other common symptoms include: fever, chills, general achiness, headache and fatigue. The rash usually occurs as a band of blisters wrapping around one side of the body from the spine to the breastbone.
It can occur on occasion on one side of the face or around the eye. Shingles near the eyes can lead to permanent damage and should be treated immediately. The most common complication is postherpetic neuralgia, in which irritation and inflammation occurs inside nerves, causing a persistent, painful condition that can last for months to years and is hard to control.
Most American adults, felled by chickenpox as children before the advent of the now-routine childhood vaccination that protects against it, carry some risk of developing shingles. It's most common in people 50 or older; the risk increases with age. Those with weakened immune systems are at higher risk. It's unclear why the virus re-emerges, but the lowered immunity to infections that comes with age may play some role.
Shingles also can reoccur. More than 5 percent of patients who had shingles reported an additional outbreak.
Shingles is contagious - but not in straightforward ways. Exposure to a person with shingles will not cause shingles to occur. However, an infected individual can pass on the virus to children who never have had chickenpox; the newly infected kids, though, develop chickenpox, not shingles and they would need to come into contact with the open blisters of the shingles rash. In chickenpox, the virus is airborne from the upper respiratory tract, allowing it to be passed by coughing or sneezing, making its infectiousness much worse. Until shingles scab over, the condition is contagious.
There are antivirals that can fight the infection. And there is a vaccine to protect against shingles. The federal Centers for Disease Control and Prevention recommend the shingles shot for those 60 and older, unless they: have a suppressed immune system, leukemia or lymphoma; are HIV-positive; or are allergic to any vaccine ingredients. A recent study, published in the Journal of the American Medical Association, found the vaccine reduced the incidence of shingles outbreaks by 55 percent, even in the oldest populations. Even if it doesn't prevent shingles for all who receive it, the vaccine can lead to milder cases than might otherwise occur, the study showed. It also deemed the vaccine 66 percent effective in preventing postherpetic neuralgia. The vaccine, introduced in 2006, is underutilized: A CDC study in the American Journal of Preventive Medicine says fewer than 7 percent of U.S. seniors chose this inoculation.
The study cites cost as one prohibitive factor. Most insurance and Medicare will pay for the costly vaccine. Because the vaccine must remain frozen until just before it is administered, other woes arise: Many physicians don't keep freezers in their offices, so they cannot store the vaccine. So the patient either has to go to the pharmacy to buy the vaccine and return to the doctor's office to receive it, or, if the facilities are available, have it administered in the pharmacy itself.
There also have been vaccine shortages. Merck, the vaccine's manufacturer, filled most back orders in December but wrote in January to customers that demand for its product remains "dynamic" with more backorders expected this year.
Despite the vaccine's challenges, the U.S. Food and Drug Administration will consider whether to approve it for those ages 50 to 59, this after an October study showing it decreased the disease's incidence by 70 percent as compared with a placebo.
If you fit the criteria to benefit potentially from the shingles vaccine, I recommend you protect yourself. Get inoculated against this painful illness. Even if you don't recall your childhood chickenpox infection -- it may have been so mild you didn't recognize you had it -- reducing the potential, long-lasting complications of the disease is well worth it.