Chickenpox Vaccine Still Underused
Immunizations are probably responsible for saving more children’s lives than any other medical development in the history of this country. Yet, six years after its approval by the Food and Drug Administration, an immunization designed to protect children against varicella--the virus that causes chickenpox--still has not gained complete acceptance.
Despite the urgings of the American Academy of Pediatrics and the federal Centers for Disease Control and Prevention, a significant percentage of American children are not receiving varicella vaccine. Public health experts are concerned that some children could pay a tremendous price for missing this immunization. Although chickenpox is usually a relatively mild illness (five to seven days of fever and fatigue, accompanied by a blister-like rash over much of the body), it can result in some serious--even life-threatening--complications.
From a public health perspective, statistics favoring the use of varicella vaccine are so compelling that several states have passed laws requiring this immunization before a child can be admitted to school or day care. In July, such a law will go into effect in California. The law requires that all children enrolling in day care or preschool and all new entrants into elementary school must provide either proof that they have been vaccinated against varicella or documentation that they have had chickenpox.
Before varicella vaccine became available in 1995, nearly 4 million Americans were diagnosed with chickenpox every year, and the disease accounted for approximately 10,000 hospitalizations and 100 deaths annually.
In spite of these alarming statistics, some parents and physicians fear that the benefits of varicella vaccine may not be outweighed by potential risks. They view chickenpox as a mild--almost “normal”--disease of childhood and see the use of varicella vaccine as too much treatment for too little disease. Others are concerned that the immunity created by this vaccine may wear off over time. There also are concerns about the vaccine’s safety.
As a result, some physicians do not even offer varicella vaccine to their patients, and some parents reject it when given the option.
In fact, most of these concerns about the vaccine are unfounded. Complications from chickenpox are far more common than most people imagine. For every 1,000 people who develop chickenpox, two or three will require hospitalization. If a woman is infected with varicella during early pregnancy, a variety of fetal abnormalities can result, including limb malformations; infection very late in pregnancy can cause severe disease, even death, of the newborn. The likelihood of suffering complications from chickenpox increases with age--the risk of death, for example, is about 20 times higher for adults than it is for children.
Several thousand immunized children are currently being monitored to determine exactly how long protection against chickenpox lasts. To date, there is no evidence to suggest that immunity is lost over time. (Studies in the U.S. indicate that protection lasts for at least 11 years; Japanese studies show that protection lasts at least 20 years.) If, at some point, immunity is found to wane, a booster shot might become necessary.
Finally, the vaccine is thought to be remarkably safe. A recent study reported in the New England Journal of Medicine concluded that most adverse events associated with the vaccine are minor and that serious consequences occur rarely. The most common side effects associated with varicella vaccine include minor rashes and pain, redness, and swelling at the injection site.
This immunization does not provide 100% protection against chickenpox; about 15% of those immunized remain susceptible to developing a mild case of the disease. So why do almost all experts recommend the use of varicella vaccine? Because it is almost 100% effective in preventing serious cases of chickenpox and life-threatening complications. Among people who receive varicella vaccine, more than 97% of severe chickenpox infections are prevented, and deaths from this disease fall to nearly zero.
Infectious disease experts at the CDC and the American Academy of Pediatrics recommend a single shot of varicella vaccine for all healthy children, ages 12 months to 12 years, who are entering child-care facilities or elementary schools. They also recommend immunizing adolescents and adults who have never had chickenpox, and who are at risk of developing it or at risk of developing complications from it if they contract it.
This includes people who live or work in environments where exposure to varicella is likely (teachers of young children and day-care employees, for example), nonpregnant women of childbearing age, adolescents and adults living in households with children, and people traveling outside the United States.
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Dr. Jonathan Fielding is director of public health and health officer for Los Angeles County Department of Health Services. Dr. Valerie Ulene is a board-certified specialist in preventive medicine practicing in Los Angeles. They can be reached at ourhealth@dhs.co.la.ca.us. Their column appears the second and fourth Mondays of the month.
