Experimental shingles vaccine proves effective in nationwide study

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Experimental shingles vaccine proves effective in nationwide study

Stronger version of chickenpox vaccine cuts incidence and severity of

shingles in older adults -

In one of the largest adult vaccine clinical trials ever, researchers

have found that an experimental vaccine against shingles (zoster

vaccine) prevented about half of cases of shingles--a painful nerve and

skin infection--and dramatically reduced its severity and complications

in vaccinated persons who got the disease. The findings appear in the

June 2 issue of The New England Journal of Medicine.

The Shingles Prevention Study, conducted over 5 ½-years, was led by the

Department of Veterans Affairs (VA) and carried out in collaboration

with the National Institute of Allergy and Infectious Diseases (NIAID),

part of the National Institutes of Health (NIH), and Merck & Co., Inc.

(Whitehouse Station, NJ).

" This is very promising news for older persons, " says E.

Straus, M.D., an infectious diseases specialist at NIAID and Director

of the NIH National Center for Complementary and Alternative Medicine,

who participated in the design, oversight and conduct of the trial.

" These striking results indicate for the first time that we can use a

vaccine to prevent shingles, one of the most common and debilitating

illnesses of aging. And among vaccine recipients who did get shingles,

the episodes generally were far milder than they otherwise would have

been. "

" For some people, shingles can result in months or even years of

misery, " comments study leader N. Oxman, M.D., an infectious

disease specialist at the San Diego VA Healthcare System and the

University of California, San Diego.

Shingles, also known as herpes zoster, is caused by reactivation of the

virus that causes chickenpox. Once chickenpox infection has run its

course, the virus is not eliminated; rather, it retreats to clusters of

sensory nerve cells usually located near the spinal cord, where the

virus persists in a dormant state. As immunity weakens with advancing

age, the virus can reactivate, multiply in and damage sensory nerve

cells to cause pain. It then migrates to the skin, causing the

blistering rash of shingles.

Generally, shingles first manifests as pain, itching or tingling in an

area of skin on one side of the body or face. Then a painful blistering

rash develops in that same area of skin; the rash can take two to four

weeks to heal.

Anyone who has had chickenpox--which includes most adults in the United

States--could develop shingles, though not all will. The two major risk

factors are increasing age and declining immunity. Half of all people

who live to age 85 will get the disease. Experts estimate more than a

million new cases of shingles occur in the United States each year.

The trial was conducted at 22 study sites nationwide, including 16 VA

medical centers and six clinical research sites outside the VA system

coordinated through NIAID. Between November 1998 and September 2001,

the multicenter research team enrolled more than 38,500 men and women

age 60 or older into the study. Half of the participants received a

single injection of the zoster vaccine--a live, weakened form of

varicella-zoster virus, the virus responsible for chickenpox; the other

half received a placebo vaccine. Neither the researchers nor the

participants knew who received vaccine and who received placebo until

after the study was over. The zoster vaccine used in the study,

manufactured by Merck, is a new, more potent version of the chickenpox

vaccine used to prevent chickenpox in millions of American children

every year since 1995. The zoster vaccine was developed specifically

for study in older adults.

During an average of more than three years of follow-up, the vaccine

reduced the incidence of shingles by 51 percent: 642 cases of shingles

occurred among those in the placebo group compared with only 315 in the

vaccinated group. Among all vaccine recipients, the total burden of

pain and discomfort due to shingles was 61 percent lower than in

placebo recipients. Moreover, the zoster vaccine reduced the incidence

of postherpetic neuralgia (PHN)--a form of chronic nerve pain that is

the most common serious complication of shingles--by two-thirds

compared with placebo. The vaccine was well tolerated, with the rates

of serious adverse events low and local reactions at the vaccination

site generally mild.

" As people live longer, and the proportion of older people in our

population increases, it is highly likely that the prevalence of

shingles will increase. A preventive shingles vaccine would be an

enormous boon for the health and quality of life of seniors, " says

S. Fauci, M.D., NIAID director. " We are extremely gratified

that this public-private partnership has led to these exciting results,

which have the potential to greatly benefit seniors in years to come. "

Approximately 12 percent of older people with shingles experience pain

lasting for 3 months or longer (the definition of PHN used in the

study). As people age, however, shingles-associated nerve pain

increases in frequency and severity. This complication may occur in

nearly one-third of persons with shingles who are 60 years of age or

older.

Patients with PHN often describe the pain as burning, throbbing,

aching, stabbing or shooting, and it can cause both physical and

emotional suffering. What can be most distressing and debilitating,

according to these patients, is that at least 90 percent of them have

allodynia--pain caused by something that ordinarily is not painful,

such as clothing touching the skin, or a cool breeze. Simply dressing

and having a shirt touch the side of the body that is affected can be

excruciating.

Postherpetic neuralgia is difficult to treat. Antiviral medications can

speed the healing of shingles and reduce the severity of nerve damage

caused by the disease, but only if these medications are used within 72

hours of the first sign of a shingles rash. Thus, it is important for

people to recognize the symptoms of shingles and get to a doctor

quickly. Antiviral medications do not help relieve PHN once it has

begun.

The researchers emphasize that the zoster vaccine was tested only as a

preventive therapy and is not intended as a treatment for those who

already have shingles or postherpetic neuralgia. On April 25, Merck

announced that it had submitted a license application to the Food and

Drug Administration for the zoster vaccine. If approved for use, the

research team estimates the vaccine could prevent 250,000 cases of

shingles that occur in the United States each year and significantly

reduce the severity of the disease in another 250,000 cases annually.

The study was funded by the VA and by Merck, which supplied the vaccine

and placebo. The R. and V. Fund for Shingles Research

provided additional funds.

NIAID is a component of the National Institutes of Health, an agency of

the U.S. Department of Health and Human Services. NIAID supports basic

and applied research to prevent, diagnose and treat infectious diseases

such as HIV/AIDS and other sexually transmitted infections, influenza,

tuberculosis, malaria and illness from potential agents of

bioterrorism. NIAID also supports research on transplantation and

immune-related illnesses, including autoimmune disorders, asthma and

allergies.