Never Had Chickenpox? Read This
Sept. 8, 2000 -- A vaccine against chickenpox is effective for
healthy adults, and it's protective over several years, according to a
presentation made in New Orleans this week at a meeting of the Infectious
Diseases Society of America. The vaccine is now highly recommended for adults
who have not contracted chickenpox in the past.
Chickenpox is an infection of the varicella-zoster virus that
is usually contracted in childhood and causes a blister-like rash all over the
body that lasts for 14 to 17 days. Most people who have had it say it felt like
their bodies were covered in mosquito bites. The disease is very contagious:
90% of people who have never had the disease themselves and are exposed to
someone with it will catch it.
While chickenpox is usually little more than an itchy
annoyance, it does have a serious side. Before the vaccine was available,
almost everyone living in the U.S. suffered from the condition by the time they
reached adulthood, for an estimated four million cases, 11,000
hospitalizations, and 100 deaths each year. Complications of chickenpox include
deep infections at the site of a blister, dehydration, and inflammation of the
heart. Encephalitis and meningitis can also occur if the virus infects the
brain. These complications are especially more common and severe in older
A vaccine against chickenpox, known as Varivax, was first
developed in Japan in 1975, and has been approved for use in the U.S. since
1995. It is a recommended vaccine for all children beginning at age one. Since
its approval, monitoring stations set up across the country have determined
that Varivax is a safe and effective vaccine for children, reducing the
incidence of the disease as well as the risk of complications and need for
What remained to be seen was whether the vaccine worked
long-term in adults. The data from this presentation suggest that indeed it
The vaccine is highly effective in adults, presenter Krow
Ampofo, MD, tells WebMD. "Long-term immunity persists. [Moreover], for
those who were unfortunate enough to develop chickenpox [despite vaccination],
the disease is milder in terms of the number of [blisters], days sick, and
recovery time." Ampofo is a fellow in pediatric infectious diseases at
Columbia-Presbyterian Hospital in New York City.
Ampofo and his team studied more than 450 adults who were
vaccinated against chickenpox and followed them for more than eight years.
Overall, 9% of them developed chickenpox. But only about 20% of those exposed
to chickenpox actually contracted the disease. The unlucky few who did come
down with the disease suffered a relatively mild attack.
Most importantly, the proportion of vaccinated adults who came
down with the disease did not increase over time. Furthermore, for those who
developed chickenpox despite vaccination, the severity of symptoms did not
worsen as the time since vaccination increased. This indicates that the vaccine
maintains its protective power for several years.
Side effects of vaccination did sometimes occur but were mild.
They included pain at the site of injection and rash that occurred within six
weeks of vaccination.
According to Ampofo, the vaccine, "is highly recommended
for susceptible adults. That is, adults who haven't had chickenpox before. If
they're not sure whether they've had chickenpox in the past, it's possible for
their physician to test [them]."