News From Terre Haute, Indiana

November 21, 2012

Vigo has largest active chickenpox outbreak

Indiana’s medical chief answers questions

The Tribune-Star

TERRE HAUTE — Vigo County “is experiencing the largest known outbreak of chickenpox in the nation,” according to Dr. Joan Duwve, chief medical officer with the Indiana State Department of Health.

The Tribune-Star’s Sue Loughlin, who has been following the story for days, submitted a list of questions about the outbreak to Dumve, who emailed the following responses:

Question: From the perspective of the Indiana Department of Health, how serious is the chickenpox outbreak in Vigo County?

Answer: Chickenpox is a very contagious disease, and Vigo County is experiencing the largest known outbreak of chickenpox in the nation. Vigo County usually has less than 10 cases a year; however, since the end of September, Vigo County has reported 84 cases which would meet the definition of an unusual occurrence of disease. Prompt identification, investigation and control of chickenpox outbreaks are important. Even mild cases can be contagious.

(On Monday, the Vigo County Health Department erroneously reported that there have been more than 100 cases of chickenpox. The correct number as of Tuesday was 84, according to Joni Wise, health department administrator).

Q: Do any other counties in Indiana have an outbreak?

A: Neighboring Parke County also has an outbreak of varicella in a school. Parke County has reported eight cases to date.

Q: Any thoughts as to why Vigo County is having an outbreak, and not other counties? We’re hearing it’s a “breakthrough” chickenpox often affecting children who have already been immunized.

A: We wish we knew why Vigo County is having an outbreak. The original case was an unvaccinated person attending school and may have introduced the virus into the school, although chickenpox may also have been circulating in the community.

Chickenpox is readily transmitted in preschool and school settings. Two doses of chickenpox vaccine is 90 percent effective at preventing disease. So, although one out of every 10 children who [is] fully vaccinated may still be susceptible to disease. Vaccination will prevent disease in nine out of every 10 children exposed.

To prevent outbreaks, communities must maintain very high levels of immunization. A less severe form of chickenpox called breakthrough chickenpox may occur in anyone who has received one or two doses of varicella vaccine, even if appropriately administered. It presents atypically, often with a maculopapular rash that may resemble bug bites, and few or no vesicles.

Chickenpox in a vaccinated person is much milder than chickenpox in an unvaccinated person. Vaccinated children with breakthrough chickenpox disease usually have a low-grade or no fever, and fewer than 50 lesions.  

Q: The health department locally said it can not really “police” all the day care/child care facilities here unless it receives reports of chickenpox at a particular facility.

What is your advice/recommendation to parents and child care/day care providers with regard to the current outbreak?

A: Local health departments and the Indiana State Department of Health are investigating these cases with guidance from the Centers for Disease Control and Prevention. We are asking for assistance from medical providers in the state. We are asking them to consider the diagnosis of varicella in patients showing signs and symptoms compatible with chickenpox disease or breakthrough varicella infection.

If you are a healthcare provider and you suspect chickenpox or breakthrough chickenpox in a patient, please call your local health department and consider testing the patient for varicella.

We are also asking health care providers to give the second dose of varicella vaccine to preschool children affected by the outbreak. The second dose of chickenpox vaccine should be given at least 28 days after the first dose, and at least 28 days after another live viral vaccine, like MMR or flu-mist. The second chickenpox vaccine administered to preschool students during this outbreak will count as the second dose required for school attendance, as long as it is given according to these guidelines.  

Q: Some people believe the situation is being “overblown” and that past generations had chickenpox without any serious consequences. Why is it so important that children be immunized against chickenpox?

A: Chickenpox (varicella) used to be very common in the United States before the chickenpox vaccine became available in 1995. In the early 1990s, an average of 4 million people got chickenpox; 10,500 to 13,000 were hospitalized (range, 8,000 to 18,000); and 100 to 150 died each year.

Most of the severe complications and deaths from chickenpox occurred in people who were previously healthy. Each year, more than 3.5 million cases of varicella, 9,000 hospitalizations, and 100 deaths are prevented by varicella vaccination in the United States.