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About Zostavax®

What is Zostavax®?

Zostavax® (pronounced "ZOS tah vax") is a new vaccine to reduce the risk of shingles (also known as Zoster) and shingles-associated nerve pain and other serious complications. It is for use in people 60 years of age and older. Zostavax® was licensed to Merck by the Food and Drug Administration (FDA) on May 25, 2006. Zostavax® is manufactured by Merck & Co., Inc., of Whitehouse Station, New Jersey.

Generic name: Zoster Vaccine Live (Oka/Merck)

Zostavax® is the only Zoster vaccine on the market. This vaccine can help prevent an illness that affects many older Americans and often results in significant chronic pain.

The shot costs about $150 and that doesn't include the doctor's charge to administer it.

Ingredients in Zostavax®

The active ingredient in Zostavax® is a weakened form of the varicella-zoster virus. The inactive ingredients are sucrose, hydrolyzed porcine gelatin, sodium chloride, monosodium L-glutamate, sodium phosphate dibasic, potassium phosphate monobasic, and potassium chloride.

How does Zostavax® work?

Zostavax® is a live virus vaccine that boosts immunity against varicella-zoster virus. This is thought to be the mechanism by which the vaccine protects against Zoster and its complications. The vaccine is given as a single injection under the skin, preferably in the upper arm.

Effectiveness of Zostavax®

Zostavax® was studied in approximately 38,000 individuals throughout the United States who were 60 years of age and older. Of these 38,000 people, half received Zostavax® and half received a placebo.

All study participants were then followed for an average of three years to see if they developed shingles and, if they did, how long the pain lasted.

At the conclusion of the study, researchers found that, overall, in those ages 60 and above the vaccine reduced the occurrence of shingles by about 50%. For individuals ages 60-69 it reduced occurrence by 64%.

In addition to preventing approximately half of the cases, the duration of pain following the onset of shingles was slightly reduced in people who developed the disease despite being vaccinated with Zostavax®.

Statistics by age:
64% effective in people between the ages 60-69
41% effective for the 70-79 age group
18% effective for those 80 years of age and older

In those who were vaccinated with Zostavax®, but still developed shingles, the duration of pain was a bit shorter for them versus those who received a placebo. Specifically, the pain of those in the Zostavax® group lasted on average for 20 days and for those who received placebo, it lasted for about 22 days. The severity of the pain did not appear to differ among the two groups.

What are side effects of Zostavax®?

The most common side effects in people who received Zostavax® were redness, pain and tenderness, swelling at the site of injection, itching and headache. The percent of significant adverse events observed in the study were not different between persons who received the vaccine versus placebo.

As part of the development program, a smaller study was conducted to look more closely at safety. In this smaller study, serious adverse events for all age groups were noted more frequently in those who received Zostavax® (1.9%) than those who received placebo (1.3%). Although FDA has concluded that the available data do not establish that these events are related to the vaccine, the manufacturer will perform a Phase 4 (postmarket) study to provide additional safety information.

Possible Adverse Reactions with Zostavax®

In the largest study that was conducted to look at safety, rates of serious adverse events were similar in people who received Zostavax® (1.4%) compared to those who received the placebo (1.4%).

As part of this larger study, a smaller study was conducted to look more closely at safety. In this smaller study, serious adverse events were noted more frequently in those who received Zostavax® (1.9%) than in those who received placebo (1.3%). The numbers of deaths in each group were similar.

Before you use Zostavax®

What should I tell my health care provider before I receive Zostavax®? You should tell your health care provider if you:
  • have or have had any medical problems
  • are taking any medications, including those that might weaken your immune system.
  • have any allergies, including allergies to neomycin or have had an allergic reaction to another vaccine
  • become pregnant within 3 months of getting the vaccine
  • are breast-feeding
  • have had shingles in the past
  • may be in close contact with someone who may be pregnant
  • have had problems with your immune system
Report any exposure to Zostavax® during pregnancy by calling (800) 986-8999.

Who should not use Zostavax®?

People who are allergic to neomycin or any component of the vaccine should not receive Zostavax®. Zostavax® is a live vaccine and should not be given to individuals who have a weakened immune system caused by treatments that they are taking such as radiation, a class of drugs called corticosteroids, or due to conditions such as AIDS, cancer of the lymph, bone or blood.

Because Zostavax® is a live virus vaccine, people who are in close contact with pregnant women who have not had chickenpox should talk to their health care provider to decide if using Zostavax® is right for them.

At this time, there is not enough information from the studies to determine the risks and benefits of Zostavax® in people younger than 60 years of age.

Zostavax® has not been studied among people who have had shingles, and the effectiveness in preventing repeated episodes is unknown. However, it is unlikely that a person who has had shingles will suffer another episode.

Pregnancy and Zostavax®

Women who are or may be pregnant should not use Zostavax®.

Children and Zostavax®

Zostavax® should not be used in children and it is not a substitute for Varivax, the vaccine to prevent chicken pox. Each dose of Zostavax® contains 14 times the amount of varicella zoster virus as Varivax.

What is Shingles?

Shingles is a disease caused by the varicella-zoster virus, the same virus that causes chickenpox. After a person recovers from chickenpox, the virus lies dormant in nerve tissues. As people age, it is possible for the virus to reappear in the form of shingles, which is estimated to affect 1 in every 5 people in their lifetime.

Shingles is characterized by clusters of blisters, which develop on one side of the body and can cause severe pain that may last for weeks, months or years after the virus reappears. For most people the pain associated with the rash lessens as it heals. For those not so fortunate the pain can lasts for months after the rash has healed. This is called post herpetic neuralgia or PHN and can be severe and chronic. Zostavax® will not work to treat PHN.

There are about one million cases of shingles per year. Age and problems with the immune system may increase your risk of getting shingles. People who have problems with their immune system may have a greater risk of getting more widespread rashes and longer-lasting pain.

Can I get Zostavax®?

You can receive Zostavax® if you are 60 years of age or older, but only your health care provider can decide if Zostavax® is right for you. In general Zostavax® may not be right for you if you are;
  • allergic to any of its ingredients
  • allergic to gelatin
  • allergic to neomycin
  • pregnant or may be pregnant
  • taking high doses of steroids by injection or by mouth
  • have active TB (tuberculosis) that is not being treated
  • have a weakened immune system such as an immune deficiency, including leukemia, lymphoma, HIV/AIDS


Call your doctor right away if any medical condition you have gets worse or you develop any new or unusual symptoms after you receive Zostavax®.

General Notes

Does Zostavax® contain thimerosal? No, Zostavax® does not contain thimerosal or any other preservative.

Zostavax cannot be used to treat shingles once you have it. The Advisory Committee on Immunization Practices (ACIP), a federal panel of immunization experts, has recommended people age 60 and older receive Zostavax® to prevent herpes Zoster, or shingles.

Zostavax® represents an important medical breakthrough aimed at improving health in older people.

The duration of protection after vaccination with Zostavax® is unknown and the need for revaccination has not been defined.

Transmission of vaccine virus from varicella vaccine recipients without a VZV-like rash has been reported but has not been confirmed.

There is a theoretical risk of transmitting the vaccine virus to varicella-susceptible individuals, including pregnant women who have not had chickenpox. Pregnancy should be avoided for three months following vaccination.

Concurrent administration of Zostavax® and other vaccines has not been evaluated. Carcinogenesis, Mutagenesis, Impairment of Fertility: Zostavax® has not been evaluated for its carcinogenic or mutagenic potential, or its potential to impair fertility.

Pregnancy Category C: Animal reproduction studies have not been conducted with Zostavax®.

As of June 1, 2007, 590 reports of adverse reactions have been submitted to the Vaccine Adverse Event Reporting System (VAERS). Of those, 44 were classified as serious, defined as ?instances of hospitalization, life-threatening conditions, disabling illness, death or other medically important conditions.? Among the 44 severe reactions, there were two deaths.

Zostavax Feedback

Subj: Effect of Valtrex on the efficacy of Zostavax?
Date: 1/18/2011
What effect does Valtrex have on the efficacy of Zostavax? Should Valtrex be stopped prior to administration of Zostavax?

AskDocWeb: According to the CDC antiviral drugs may reduce the effectiveness of Zostavax. Antiviral drugs should be discontinued at least 24 hours before the administration of the varicella vaccine. Persons taking famciclovir, Acyclovir, or valacyclovir(Valtrex) should not use these drugs for at least 14 days after vaccination, by which time the immunologic effect should be established.

Read more feedback about Zostavax.

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This consumer advocate website is protected by copyright © 2002-2007 Askdocweb, Inc. All Rights Reserved. This is a layman's report on Zostavax and is not intended to replace discussions with a health care provider. Do not use the information on this forum as a substitute for your doctor's advice. Always consult your doctor before taking any drug and follow your doctor's directions. Source material: Food and Drug Administration, Ferri's Clinical Advisor, Physician's Desk Reference, and the largest community of people in the world, those who are concerned about side effects and healthcare.
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