Chickenpox Vaccine
There are approximately 3.9 million cases of chickenpox in the United States each year. 95% of all people will develop the disease – usually during the early school age years.
Although chickenpox is usually a mild illness, it can have complications associated with it. 9000 people are hospitalized and about 90 die each year. The most common complication is a bacterial infection of the skin. Chickenpox can also lead to pneumonia – either viral or bacterial, or infections of the brain. The disease is usually more severe in adults.
A vaccine for chickenpox was developed in Japan in the early 1970s and has been given to over 2 million people. The vaccine has been used in the United States since the early 1980s and has been proven to be safe and effective
The American Academy of Pediatrics recommends the chicken pox vaccine for all children over 12 months of age who have not had chickenpox. Health children over 13 years without a history of chickenpox, and have not received the vaccine should receive two doses of the vaccine 4-8 weeks apart.
The vaccine is about 95% effective at reducing serious illness. Overall, it is 70-90% effective at eliminating all disease. That means that 1-3 of every ten children who receive the vaccine can still develop chickenpox. Those children who do develop the illness will have milder cases – 15-32 lesions instead of the usual 250-500. The fever is lower and the illness lasts a shorter time. Vaccinated children who come down with the illness still can spread the disease to susceptible people.
Recent studies in Japan have shown that the immunity in some of the first patients who received the vaccine is still good 20 years later. As a matter of fact, some patients have greater immunity at 20 years than at 10 years, which suggests that they have received a "booster" effect from exposure to the wild virus.
Reactions to the vaccine are usually mild. About 20% of patients will experience soreness, redness and swelling at the site of the shot. 3-4% will develop a mild rash or bumps. This can occur up to 1 month after the immunization and can last several days. The person with the rash might be contagious and should stay away from anyone whose immune system is not working properly. 15% of vaccinees develop a fever over 102o.
People in certain high risk categories should not receive the vaccine. These include people with immune system problems, pregnant women, or someone who has received blood products in the prior several months.
Children can receive the chickenpox vaccine at the same time as other immunizations, but if they do not get the MMR and chickenpox vaccine at the same time, they should wait at least one month after receiving the MMR before getting the chickenpox vaccine. This does not hold for other immunizations.
