Chickenpox Vaccine Health Article

Shingles

Although children who have had chickenpox are immune to the disease and cannot contract it a second time, the varicella zoster virus can remain inactive in the human body. These dormant viruses are concentrated in nerve cells near the spinal cord and may reactivate in adults, causing the disease herpes zoster or shingles. The reactivated virus further infects nerve cells, causing severe pain, burning, or itching. Shingles usually occurs in people over the age of 50 and may be associated with a weakening immune system.

It is not known whether the weakened virus used for VZV can remain dormant in the body, eventually causing shingles in the same way that the naturally occurring varicella virus can. In 1998 the CDC found 2.6 cases of post-vaccination herpes zoster for every 100,000 distributed doses of VZV. In contrast there were 68 cases of herpes zoster in healthy children under age 20, following natural infection with varicella. However, as of 2004, it is too early to determine whether vaccinated children are more or less likely to develop shingles in adulthood as compared with adults who were naturally infected with chickenpox as children.

A 2002 study indicated that exposure to varicella is much higher in adults living with children and that such exposure substantially boosts immunity against shingles. The authors of the study predicted that mass vaccination against varicella will create an epidemic of herpes zoster, affecting as many as 50 percent of those who were between the ages of ten and 44 at the time that the vaccine was introduced.

Consequences of chickenpox

Chickenpox is highly contagious and easily transmitted among children through personal contact, coughing, or sneezing. The disease is characterized by red spots on the face, chest, back, and other body parts. These spots fill with fluid, rupture, and crust over. Symptoms of chickenpox may not appear for as long as two to three weeks following infection. The virus is contagious from one or two days before the first rash appears until the blisters have formed complete scabs and no new rash has appeared for 24 hours. This may take from five days to two weeks. Thus the varicella virus can spread very rapidly within families and among groups of children in school and daycare.

In most instances chickenpox is not a serious disease, although the itchy lesions and fever and other mild flu-like symptoms may cause a week or two of discomfort. However the disease can have serious complications. Scratching the pox can cause bacterial infection that can lead to permanent scars. In rare cases chickenpox can lead to the following:

• muscle aches
• sore throat
• ear infections
• pneumonia
• arthritis
• neurological symptoms, including shakiness
• encephalitis, an inflammation of the brain

In the United States more children die of chickenpox than of any other disease that can be prevented by a vaccine. Prior to the introduction of VZV, there were about 100 deaths and 12,000 hospitalizations annually as a result of chickenpox infections. Approximately 40 percent of the deaths and 60 percent of the hospitalizations occurred in children under age ten. Teenagers and adults, as well as children with leukemia or other cancers or with impaired immune systems, are at particular risk for severe chickenpox and its complications. Babies whose mothers contracted chickenpox during pregnancy are at risk for multiple birth defects. Babies whose mothers contract chickenpox shortly before or after giving birth are at risk of developing a severe form of the disease. As many as 5 percent of these babies die. Most high-risk children and non-immune adults contract chickenpox from unvaccinated children.

Children with chickenpox miss an average of five to six days of school and their parents miss an average of three to four days of work while caring for them. The CDC estimates that, including direct medical costs and indirect societal costs, $5.40 is saved for every $1.00 spent on childhood VZV immunization.