The chickenpox vaccine has nearly eliminated deaths from the disease in children, a new study shows.
The death rate from chickenpox fell 97% among people under age 20 from 1990-1994 to 2005-2007, according to a report from the Centers for Disease Control and Prevention in today's Pediatrics. "Chickenpox deaths in children are becoming a thing of the past," says the CDC's Jane Seward, the study's co-author.
That's an impressive achievement, considering the study measured the effect of only one dose of vaccine, which was first recommended in 1995, Seward says. When the vaccine was introduced, the CDC recommended a single shot for babies at age 1 to 1, which prevents about 85% of infections. In 2006, the CDC recommended a second dose at age 4 to 6, hoping to protect even more kids.
Significantly, vaccination has protected even babies too young to receive it, because keeping the virus out of circulation also protects those who aren't vaccinated, a phenomenon known as "herd immunity."
High vaccination rates in older children have "really shut down transmission of the virus," Seward says.
Although many adults remember chickenpox as a nuisance, sickening children for a week with a fever and itchy rash, the disease can lead to deadly complications, such as pneumonia, a brain inflammation called encephalitis and even infection with flesh-eating bacteria, Seward says. Before the vaccine was approved in 1995, about 150 people a year died from the disease and 11,000 were hospitalized, she says.
Chickenpox also can be extremely disruptive, forcing parents to take a week off work, says Paul Offit, chief of infectious disease at Children's Hospital of Philadelphia, who wasn't involved in the study. Before the vaccine, the 4 million annual cases of chickenpox resulted in $330 million in health care costs and $1.5 billion in "societal" costs, such as lost work time, according to a 2010 analysis in Pediatrics.
Some parents remain skeptical about the vaccine's benefits, arguing that most chickenpox cases are mild. But given the vaccine's track record of safety -- doctors have administered 65 million doses in the past 16 years -- Seward says children are much better off with a vaccine than getting chickenpox. "You can't look around a classroom and tell which of the healthy children who gets it is going to be the unlucky one who dies," she says. "Do you want to take that chance?"
The chickenpox virus can live silently in the nervous system for years, Offit says. People who have had it can develop a painful condition caused shingles if the virus "reactivates" later in life. Because people who are vaccinated receive a weakened version of the virus, their cases of shingles are likely to be milder than those caused by the "wild" virus, Offit says.
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