Chicken Pox Vaccine

A vaccine to prevent chicken pox (also known as varicella) became available in the United States in May, 1995. Both the American Academy of Pediatrics and the U.S. Public Health Service have recommended that all infants 12 to 18 months of age receive this vaccine, and that it also be given to older children who might be susceptible to chicken pox. However, there have been questions about how long the immunity from the vaccine lasts and whether, in fact, children really need to be vaccinated against an illness that seems as mild as chicken pox.

Another question is whether the vaccine will work as well in the "real world" as it did when it was being studied under strict experimental conditions. Because the vaccine has to be kept frozen and then injected within 30 minutes after it has been mixed, some doctors worried that conditions in the typical health care provider's office or clinic might not be ideal, so the vaccine might not be very effective.

However, when researchers recently studied use of the vaccine under just these kinds of conditions, they found it was "highly effective" in preventing chicken pox during an outbreak of this illness at a child care center in Georgia. (Izurieta HS et al: Journal of the American Medical Assoc-iation, November 12, 1997, pp. 1495-1499)

An editorial that accompanied this latest study reviewed other questions about the vaccine and attempted to provide some answers. A common question concerns how long immunity lasts. Though the vaccine only became available for the general population in 1995, it was under study for many years before that, and the latest information indicates that immunity lasts at least 20 years.

Another concern is that people who receive the vaccine might be at higher risk for shingles (also called zoster), a very painful skin condition related to chicken pox but occurring in adults. The best evidence indicates that, if anything, the vaccine may actually reduce that risk.

In their conclusion, the editorial writers ask "Do the benefits of universal immunization outweigh the risks?" They answer that chicken pox is not a trivial illness, and wonder "why would we deny children protection from a disease that at best is an unpleasant rite of passage when the preponderance of evidence about the benefits of vaccination are so favorable? The time has come to stop the procrastination and just do it!" (Shapiro ED & LaRussa PS: Journal of the American Medical Association, November 12, 1997, pp. 1529-1530)

Comment by Child Health Alert: The writers of the above editorial are highly respected experts in the field of children's vaccines, and their perspective and opinions are important. We would offer three additional points:

First, many parents and doctors think of chicken pox as a mild and even trivial illness. That may be true in most cases, but among the millions of children each year who get the disease, there are still quite a few who suffer serious complications.

Second, though immunity has been estimated to last at least 20 years, it's important to know that people who were among the first to get the vaccine still have immunity from it--it's just that the vaccine hasn't been studied for much more than 20 years. Most experts predict immunity will last well beyond 20 years, and even if it doesn't, a second ("booster") shot of vaccine would be a simple way to solve the problem.

Third, there is a growing practical reason to have all children get the chicken pox vaccine. As more and more children receive it, there will be less chicken pox around in the community. A child who isn't vaccinated, therefore, may not come in contact with chicken pox until adulthood. At that point, he or she would not have immunity, and chicken pox in adults is a much more serious illness than it is in children.

For all these scientific and practical reasons, then, we think the recommendations for universal use of the chicken pox vaccine in children are worth taking seriously.

This article is provided by Child Health Alert