The vaccine against chickenpox is the one parents are most likely to refuse for their children, probably because the disease itself is usually relatively mild compared to killers like polio and smallpox. That, and the fact that many parents know that if their kid is the only one in the school who hasn't been vaccinated, she will still benefit from the "herd immunity" provided by the other children.
But the trend toward parents refusing chickenpox (aka varicella) vaccine means more sick kids. Children who didn't receive the vaccine were nine times as likely to get the disease as were similar children who did get vaccinated, according to researchers at the Kaiser Permanente Institute for Health Research in Colorado. That might sound like a big "duh." Vaccines are supposed to keep kids from getting sick, after all. But the study authors, writing in the Archives of Pediatric and Adolescent Medicine, say the results are relevant, providing "evidence to counter the misperception among some parents that unvaccinated children are not at risk for vaccine-preventable disease."
I vividly remember having chickenpox as a child; oceans of calamine lotion did nothing to ease what I remember as weeks of misery, with itchy, crusty sores all over my body. (Let's not even talk about those itchy pox inside my mouth.) So I'm all for a vaccine if it saves my kid from that suffering. In most children, the disease is relatively mild, but that's not always the case. Before the varicella vaccine was mandated in 1995, about 100 children a year died from the disease each year in the United States. Chickenpox is fatal in about 15 percent of people with an impaired immune system, many of whom can't tolerate vaccines.
The downside, in many parents' minds, is that the first chickenpox vaccine is given to babies between 12 and 15 months of age, at the same time that they're getting the MMR (measles, mumps, rubella) shot. That feels like a lot of shots for one little baby. Giving the MMR and varicella shots separately in the same office visit rather than giving the combined MMRV shot decreases the risk that a child will have a fever after getting the shot and also reduces the risk of febrile seizure (although the risk is still very rare—rising from 4 children for every 10,000 vaccinated to 8 for every 10,000 with the MMRV). But that means two shots. Ouch. (The Centers for Disease Control and Prevention spells out the pluses and minuses of combining MMR and varicella shots on its website.)
When the chickenpox vaccine debuted in 1995, it was given as a single dose. But one shot turned out to be only about 85 percent effective, and its effectiveness waned after a year; in one Maine elementary school, a chickenpox outbreak among children who had been immunized raged from October 2005 to January 2006, with 350 children falling ill. The outbreak was stopped only when the children were given a second shot. So in 2006, the Advisory Committee on Immunization Practices recommended that children receive a second shot between ages 4 and 6. That seems to confer immunity in most children, though 1 to 4 percent of immunized children still do get very mild "breakthrough" cases.
In the prevaccine days, parents would hustle their kids over to play with a child who had chickenpox. The thought was to have all the kids exposed and get chickenpox over with, reducing the odds of their becoming more seriously sick as adults. So, what will it be: chickenpox shots or a "chickenpox party"? Here's a chart from the National Network for Immunization Information listing the pros and cons of chickenpox parties vs. immunizations. I remember those horrible itchy spots all too well, and they were no party, so I went with the shots for my child. What will you choose?