The Facts You Need to Know About the Chicken Pox Vaccine

How to decide if your family should get it

chicken pox vaccine
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Thanks to the chicken pox vaccine, incidence of the illness has decreased dramatically. Varivax is the live-virus vaccine that produces persistent immunity against chicken pox and has been in widespread use since the mid-1990s.

Should you or your family members be vaccinated? Make an informed decision about chicken pox vaccination with the following facts about the vaccine, its side effects, and the individuals it's designed to help.

Which Virus Strain Does Varivax Contain?

The virus used for the chicken pox vaccine is known as the Oka strain. It is an attenuated strain, meaning that it is much weaker than naturally occurring varicella is. This weaker virus infects the cells and replicates in the bloodstream, which causes the immune system to develop antibodies to fight it off.

In most cases, this infection is subclinical. This means it does not produce symptoms. If a vaccinated person gets chicken pox, the disease is mild 95 percent of the time. The length of time these antibodies stay effective is controversial, but it appears that vaccination does confer long-lasting immunity.

Side Effects of the Chicken Pox Vaccine

The side effects of the chicken pox vaccine are usually mild and include low-grade fever, mild discomfort at the vaccination site and a limited rash (of about three to five lesions) at the vaccination site.


Who Should Get the Chicken Pox Vaccine?

The chicken pox vaccine is recommended for all children between the ages of 18 months and adolescence who have not yet had chicken pox. Studies have also shown that the vaccine can prevent chicken pox or reduce the severity of the illness if it is given within three to five days of exposure to an infected person.

Some experts recommend that any healthy adult who does not have a known history of chicken pox infection be vaccinated. Some studies also show that the chicken pox vaccine may prevent or reduce the severity of shingles in adults more than 55 years of age who had a childhood bout of chicken pox.

Who Should Not Get the Chicken Pox Vaccine

Because the chicken pox vaccine contains a live virus, it is not recommended for the people with the following conditions:

  • Pregnant women
  • History of previous chicken pox infection
  • Compromised immune system
  • Exposure to the varicella virus fewer than 21 days before would-be administration of the vaccine 
  • Allergy to neomycin
  • Transfusion of IgG or other blood products within the past five months
  • Administration of aspirin or aspirin-containing products within the past six weeks

Chicken Pox Vaccine Controversies

Certain aspects of vaccination for chicken pox are either unknown or are under study. The two controversial aspects are vaccination of infants and the need for booster shots.

Currently, there are no recommendations or studies on infants who develop chicken pox during the first year of life. In older patients, booster shots may be needed to maintain adequate levels of antibodies to prevent shingles.

If you're wondering whether the chicken pox vaccine is appropriate for you or your loved ones, consult your physician.