What is varicella?
Varicella (chickenpox) is a virus that typically infects young children, but it can also infect older children and adults who are not immune.
People infected with varicella virus usually develop fever and about 300 to 500 blisters over their entire body. The virus is very contagious and is spread by coughing and sneezing.
Varicella also infects the lungs (pneumonia) and the brain (encephalitis) and sets the stage for severe skin infections (caused by “flesh-eating” bacteria).
Varicella can also infect unborn babies during pregnancy, causing birth defects or fetal death.
What is my child’s risk of getting varicella?
Before the varicella vaccine, almost all children got varicella. The varicella vaccine first became available in 1995. Since that time, the incidence of varicella infections has decreased tenfold. However, varicella infections are still common in the United States.
How is the vaccine made?
The chickenpox vaccine was made by taking natural chickenpox virus and growing it in specialized cells in the laboratory. As the chickenpox vaccine got better and better at growing in these laboratory cells, it got worse and worse at growing in children. The chickenpox vaccine represents the best of two worlds. On the one hand, the vaccine grows well enough to cause immunity. On the other hand, it doesn’t grow well enough to cause disease. Therefore, children can get immunity to chickenpox without having to suffer the potentially high price of natural infections.
Does the varicella vaccine cause any reactions?
Some children will develop reactions like pain, redness or tenderness at the site of the injection. Fewer than 5% of children will develop a few blisters after receiving the vaccine.
Can varicella re-occur?
The adult form of varicella is “Shingles”. It is a painful rash that can occur many years after having chickenpox. Chickenpox and shingles in adults can be more painful than in children. A shingles vaccine is available for adults over 50 years of age.