Chicken-Pox Vaccine 

Risks or side effects of the new chicken-pox vaccine?

Answer: 'The chicken-pox vaccine is usually well tolerated,' says E. Lawrence Hoder, MD, from the Department of Pediatric and Adolescent Medicine at Lahey Medical Center in Burlington, Massachusetts. 'The most common side effects associated with the vaccine are pain and redness at the injection site.'

Other reported side effects include respiratory tract illness, chills, fever, irritability, fatigue, sleep disturbance, gastrointestinal disturbance, rashes, itching, and joint and muscle aches, although these symptoms have not yet been positively identified as being vaccine related. Approximately three to five percent of vaccinated individuals develop a chickenpox-like rash within 5 to 30 days from vaccination. 

Causes
Chicken pox is caused by exposure to a highly contagious airborne varicella-zoster virus (VZV). The illness typically begins with fever, malaise and a rash. The rash begins as flat red patches that evolve into patches with a central blister, the classic “dew drop on a rose petal.” These patches then dry and scab. New eruptions occur daily for four to seven days. The average child gets a total of 500 chicken pox sores.

Complications in healthy children are unusual but include secondary skin bacterial infections, neurologic complications, hepatitis and Reye’s Syndrome (a serious illness that can cause recurrent vomiting, liver problems and seizures). For most children, chicken pox will be a fairly benign illness. The economic consequences due to lost time at work for caregivers usually far outweighs any health risk. For adults and immunocompromised persons, however, infection with chicken pox may cause severe complications, such as pneumonia that requires hospitalization.

“Once a person has had chicken pox, he or she will usually have a lifelong immunity to the disease,” says Dr. Hoder. “Rarely, however, a person will experience a second, milder case of chicken pox later in life.” It is important for parents to understand that having the vaccine may not provide such protection. The need for revaccination has not yet been determined. Similar to measles vaccine, a “booster” dose may be required.

Vaccinations
Currently, the American Association of Pediatricians recommends a vaccination for all susceptible children greater than one year of age. As of August 1998, the State of Massachusetts requires the vaccine (or a physician-certified reliable history of chicken pox) for entrance into daycare or preschool for children who are 19 months or older and who were born on or after January 1997; by the 1999-2000 school year, vaccinations will be required for entrance into kindergarten or for those children already in school, for entrance into 7th grade.

When Not to Vaccinate
The chicken pox vaccine should not be administered to adults or children who have the following conditions:

•          A history of hypersensitivity to any component of the vaccine, including gelatin

•          A history of an allergic reaction to neomycin

•          Blood disorders (other than simple anemia) or cancer

•          A condition or treatment resulting in an immunosuppressed state, for example, immunoglobulin deficiency, AIDS, or corticosteroid therapy

•          A family history of an immunodeficiency

•          Active, untreated tuberculosis

•          Any illness that produces a fever

•          Pregnancy (or a considered pregnancy in the three-month period following administration of the vaccine)

Precautions
Individuals who receive the vaccine should avoid taking aspirin (salicylate) for at least six weeks after the vaccination. Because vaccinated individuals may be able to transmit the virus to close contacts, vaccinated persons should avoid close association with susceptible, high-risk persons. This risk of transmission is probably small and is more likely to occur if the vaccinated individual developed a rash after vaccination.