Chickenpox, the highly contagious disease that has attacked scores of children for generations, is not as commonplace as it used to be in the United States due to routine chickenpox vaccinations, which have reduced the spread of the disease and nearly eliminated chickenpox-related deaths. However, many pediatricians are concerned that some parents’ reluctance to vaccinate their children could cause a resurgence of the disease, said Dr. Robert Mendelson, a pediatrician and spokesperson for the American Academy of Pediatrics.
Prior to the introduction of the one-dose, chickenpox vaccine in 1995, almost every child in the United States got chickenpox by the age of 15, and there were about 4 million cases of chickenpox each year, said Dr. Mona Marin, an epidemiologist with the Centers for Disease Control and Prevention (CDC) Division of Viral Diseases. In recent years, the estimated average number of chickenpox cases has dropped to about 400,000 to 450,000 annually, that is a 90 percent reduction, Dr. Marin said, adding that the United States was the first country to introduce the chickenpox vaccine.
Deaths and hospitalizations due to chickenpox have also drastically declined since 1995, according to a study conducted by the National Center for Immunization and Respiratory Diseases. The single-dose vaccine has reduced the death rate from chickenpox among children and young people up to 20 years old by 97 percent, said Dr. Marin, co-author of the study. Among people of all age groups, the study shows that the vaccine reduced deaths by 88 percent.
“In the pre-vaccine years, there were 105 deaths annually in which chickenpox was the main cause of death in all age groups, and now in the last three years we have had 15 deaths annually in which chickenpox was the main cause,” Dr. Marin said.
Additionally, prior to the vaccine, CDC statistics show that there were about 11,000 chickenpox-related hospitalizations annually. Between 2000 and 2006, the number of hospitalizations dropped to an average of about 3,500 annually. This new data indicates that chickenpox is causing less of a burden on parents, the nation’s burgeoning health-care system, and the economy due to loss productivity from missed school and work days.
While the decrease in chickenpox cases is good news for Dr. Mendelson, who recalls having a medical practice full of chickenpox-infected children from the 1960s until 1995 when vaccinations began, he cautions that parents still need to be vigilant about getting their children vaccinated to prevent a resurgence of the disease.
“We are seeing more vaccine refusals in Oregon and more cases of chickenpox,” said Dr. Mendelson, who resides in Portland, Oregon. “Because chickenpox is not now universal, some people assume that chickenpox is no longer a threat, but because of international travel and people refusing the vaccine, the number of cases of chickenpox is increasing again especially in communities where the immunization refusal rate is high.”
Chickenpox is an airborne disease caused by the varicella zoster virus. According to the CDC, symptoms of the disease include an itchy, blister-like rash, fever, headache and tiredness. The rash usually occurs on the face, scalp, chest and back, but it can cover the entire body, causing between 250 to 500 blisters. The disease lasts from five to 10 days and is spread through coughing, sneezing or direct contact with an infected person.
Although chickenpox is perceived as a mild disease, Dr. Marin insists that people should not take it lightly, because chickenpox can have serious consequences for people of all ages especially for infants and adults who are not immune to the disease. “In adults, one of the most common complications is pneumonia due to the chickenpox virus or a bacterial infection, and among children one of the most severe complications is infection of skin lesions that can lead to sepsis [blood poisoning], and this can affect all of the organs in the body. There are also neurological complications like encephalitis [swelling of the brain] and meningitis, and small children can have severe dehydration.”
The chickenpox vaccine is much safer than getting chickenpox disease, as most people only experience mild soreness at the injection site, Dr. Mendelson said.
People who have had chickenpox are immune to the disease for life, but some of the varicella zoster virus remains in the body, Dr. Marin said. She explained that the virus may lay dormant for years without manifesting any symptoms, but it may reactivate at anytime and reappear as shingles, a painful condition which causes blisters on one side of the face or body. Shingles can last up to four weeks or more. In rare cases, shingles can lead to loss of vision, paralysis on one side of the face or long-term nerve pain, Dr. Mendelson said. A shingles vaccine is available, but it is only recommended for adults age 60 and older, because about half of all shingles cases occur in this age group.
The CDC recommends that everyone who is not immune to the disease receive two doses of the vaccine especially those who are at high risk for exposure like young children, and unvaccinated health care workers, teachers, child care employees, international travelers, military personnel, adults living with young children and women of childbearing age. The two-dose vaccine, introduced in 2006, has proven to be about 98 percent effective in preventing chickenpox, Dr. Marin said. Children should get their first dose between ages 12 and 15 months, and their second dose between ages four and six. If a vaccinated person gets chickenpox, Dr. Marin said it is usually very mild with fewer skin lesions. The vaccine does not prevent shingles, but Dr. Marin said vaccinated children have a lower incidence of developing shingles.
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