01/28/2013 05:17 pm ET

Adult Chicken Pox: How Is Barbara Walters' Condition Different From Shingles?

Barbara Walters, the 83-year-old veteran news anchor and co-host of "The View," is in the hospital with chicken pox, according to news reports.

The Boston Globe reported that Walters was initially hospitalized because of a fall more than a week ago, but doctors had yet to discharge her -- because of the chicken pox.

Chicken pox, caused by the varicella-zoster virus, is often thought to be a childhood illness, but adults who haven't been vaccinated or who had never been infected with the virus before can also get it, said Dr. Jim Sears, a board-certified pediatrician and Emmy-nominated co-host of The Doctors.

It's harder for adults to "catch" chicken pox than children, since chicken pox is often spread by touch. "Kids touch each other a lot more than adults -- wiping boogers on each other, and all that kind of stuff," Sears told HuffPost. "Adults don't touch each other as much, so as you move into your adult population, just the number of people running around contagious is a lot less."

Plus, many adults who think that they've never had chicken pox before actually have had it -- the case may have just been mild enough that they didn't realize they had the infection, Sears said.

Adults have significantly fewer chicken pox infections compared to children, he explained. In fact, about 5 percent of chicken pox cases each year are in adults. But among hospitalizations for chicken pox, 33 percent of those are in adults.

Stacey Rizza, who is the chair of the HIV clinic at Mayo Clinic, an infectious disease expert and associate professor of medicine at the Mayo Clinic, told HuffPost that getting chicken pox as an adult can lead to more severe symptoms because "your immune system is not as young and ready to attack, so you get a little sicker."

Adults with chicken pox are also more likely to develop complications than kids, such as pneumonia, Rizza added.

Adult chicken pox is different from shingles, in that you must have been infected with chicken pox first in order to develop shingles. When a person contracts chicken pox, the virus never goes away throughout the person's life -- it just lies dormant in the body. Sometimes the virus never reappears, but if the immune system becomes weakened with time -- whether it's from old age, cancer, HIV, or just plain old stress -- the virus activates and erupts in the form of shingles, Rizza explained.

However, adult chicken pox is not the same as shingles. If an adult gets chicken pox, it's because he or she had never been infected with it before, according to Rizza. Or, in rarer cases, it's possible to get reinfected with the virus if the immune system is very weak.

Ultimately, Sears recommends adults who aren't sure if they've had chicken pox before get a blood test to see if they have antibodies against the virus. If they don't, then it is a good idea for that adult to get a chicken pox vaccine to avoid developing a severe case of chicken pox later in life.