First of all, chickenpox has generally been regarded by families as more of a "nuisance" disease. It is viewed as a benign, self-limiting illness. Chickenpox causes an obvious rash with lots of itching and discomfort. Kids miss about a week of school or child care, and in turn their parents or caretakers miss an equal amount of work. Everyone seems to get it at some point in their childhood and then is felt to be immune for life (it is unusual to get it more than once).
It has been argued that the more kids who get the vaccine, the less natural chickenpox will be around to cause problems. Some are aware that chickenpox is often worse in adolescents, adults, or those individuals whose immune systems can't fight infection normally. Few know the potential complications associated with chickenpox -- secondary skin infection with bacteria germs, pneumonia, or brain involvement. On the other hand, if we don't know whether a child will have a lifelong immunity, are we putting kids who receive the vaccine at risk for a disease that is more severe when they're older?
What are the benefits of the vaccine? The vaccine is generally well tolerated, provides a high degree of protection, and this immunity should last for 10 to 20 years, if not longer. There would be less medical complications, less healthcare costs, and less exposure to the natural disease by those individuals who don't handle chickenpox well. It is not known whether a booster shot will be recommended in the future.
As I have written previously, I have given the vaccine to both our kids. I do recommend it for healthy kids in my practice as I think the positives outweigh the negatives. You can't be sure when your son will get the chickenpox and whether he'll have a complication or not. Discuss it further with your son's doctor and make a decision that you're comfortable with.
For more Questions and Answers on Chickenpox see:Is the vaccine safe?
What should I do if my child was exposed to chickenpox?
Is it dangerous for a six month-old baby to get them?