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A CUP OF HEALTH WITH CDC
Nobody Wants Chicken Pox!
Prevention of Varicella: Recommendations of the Advisory Committee on
Immunization Practices (ACIP)
June 29, 2007

[Announcer] This podcast is presented by the Centers for Disease Control and Prevention. CDC
– safer, healthier people

[Matthew Reynolds] Welcome to A Cup of Health with CDC, a weekly broadcast of the
MMWR, the Morbidity and Mortality Weekly Report. I’m your host, Matthew Reynolds.
Varicella is the scientific name for chickenpox, a common childhood disease. There are
now vaccines available that can prevent chickenpox and we also that know there are
some really good reasons to prevent it. Even though many kids – and some adults –
have gotten chickenpox and suffered no ill effects beyond a few miserable days of
itching, chickenpox can be a very severe illness, especially for adolescents and adults,
pregnant women, or persons with compromised immunity. It can even cause permanent
harm to some newborns if their mothers were not immune and had chickenpox while
they were pregnant. Medical experts who advise CDC on immunizations have updated
the recommendations for the vaccines that help prevent chickenpox.

Today we will be talking with Dr. Mona Marin, a research physician in CDC’s
immunization center. Dr. Marin is the lead author of the recently published
recommendations on varicella prevention and she’s here to tell us more about that.

Welcome to the show, Dr. Marin.

[Dr. Mona Marin] Thank you, Matthew. It’s a pleasure to be here.

[Matthew Reynolds] Dr. Marin, I have pretty clear memories of having chickenpox
when I was a child. I think I was about nine years old and I was probably feeling pretty
sorry for myself when I was sick. So, from my point of view, being able to prevent
chickenpox is a great achievement I understand that the original recommendations on
varicella vaccination have been updated. Can you tell us what is different in the newer
guidance on immunization to prevent chickenpox?

[Dr. Mona Marin] Well, Matthew, there are several changes between the original
recommendations and the new report, but the main difference is the recommendation
for a routine 2-dose vaccination schedule for children. The original recommendations for
prevention of varicella in the United States, issued in 1995 and updated in 1999, called
for a 1-dose childhood vaccination program. Although great progress has been made
with the one dose program, the reports in the last years show that the number of
varicella cases has remained constant or declined minimally. In addition, outbreaks of
varicella have continued to occur in highly vaccinated school populations, and these
outbreaks are difficult to control because most of the students have already received the
one dose of vaccine as it was recommended. So these are factors that indicate the one
dose program might have achieved the limit of control. Therefore, in 2006, a routine two
dose vaccination schedule was recommended for children. And this recommendation
was based on evidence that a second dose will boost immunity and we expect to
provide further protection to the 15%-20% of children who do not respond adequately to
the first dose.

[Matthew Reynolds] From what I understand, there is more than one type of vaccine
that can be used to prevent chickenpox. What are the differences?

[Dr. Mona Marin] You are right, Matthew. Currently there are two vaccines available in
the US for prevention of chickenpox. They differ in their composition and the ages for
which they are indicated. There is a single antigen varicella vaccine for use among all
healthy persons aged 12 months or older, that is for children, adolescents, and adults.
This vaccine provides protection for chickenpox only. The other vaccine is a
combination measles-mumps-rubella and varicella vaccine, for use among healthy
children aged 12 months through 12 years. So this vaccine can be used for
simultaneous vaccination against four diseases. This combination vaccine should not be
administered to people aged 13 years or older.

[Matthew Reynolds] Who should get vaccinated and when should they get
vaccinated?

[Dr. Mona Marin] For the routine childhood vaccination: healthy children aged 12
months through 12 years should receive 2 doses of varicella vaccine, with the first dose
administered at age 12-15 months and the second dose at age 4-6 years. For persons
13 years of age or older, the recommendation is that all persons without evidence of
immunity should receive two doses of vaccine 4-8 weeks apart. And there is also a
catch-up recommendation for children, adolescents, and adults who previously had
received one dose.

[Matthew Reynolds] Are there other recommendations for varicella vaccination,
perhaps other groups that we haven’t mentioned so far?

[Dr. Mona Marin] Yes, there is a recommendation to assess prenatally the evidence of
immunity for pregnant women and vaccinate those women who do not have such
evidence, after termination or completion of the pregnancy. There is a recommendation
for vaccination of certain categories of HIV-infected persons; a recommendation for a
two-dose policy for outbreak control; and vaccination requirements for entry to child
care, school (all grades – elementary, middle, high school), college and other
postsecondary educational institutions.

[Matthew Reynolds] Are there some people who should not get the vaccine?

[Dr. Mona Marin] Yes. As a brief overview, varicella vaccines should not be given to
certain groups of people, such as those who have allergy to any components used in
the vaccines or those who have reduced immunity from any malignant condition,
including leukemia, lymphomas of any type, or other cancers affecting the bone marrow.
People with other conditions that reduce immunity - due to diseases, such as AIDS or
severe HIV infection, or due to treatment, such as high-dose steroid therapy or
chemotherapy – also should not receive the varicella vaccine. Also, varicella vaccine
should not be given to a pregnant woman. And there are other specific conditions that
are listed in the report and health-care providers can advise their patients accordingly.

[Matthew Reynolds] Are some people immune to varicella – and how would a person
know if they are immune to it?

[Dr. Mona Marin] Thank you for this question, Matthew. The new report defines a set of
criteria for health-care providers upon which they can assess whether a person is
immune or not. People should ask their health-care provider and immunity can be
assessed based on history of vaccination, history of disease, some laboratory tests, and
so on.

[Matthew Reynolds] I’ve heard the term “breakthrough varicella.” Could you explain to
us what that is?

[Dr. Mona Marin] Certainly, Matthew. Breakthrough varicella is varicella disease that
occurs in a person more than 42 days after vaccination. As you know Matthew, no
vaccine is 100% effective in preventing all disease, so some people who were
vaccinated might get the disease. While breakthrough varicella is substantially less
severe than varicella in unvaccinated persons, it is important to remember that these
cases are infectious. We expect the second dose varicella vaccination to reduce the
number of breakthrough cases to less than 1 in 10 people who got two doses of
vaccine, compared with 1 in 5 people who got one dose of vaccine.

[Matthew Reynolds] What if someone wants to learn more, they have more questions
about varicella. Where can they go? What do you recommend?

[Dr. Mona Marin] To learn more about vaccination recommendations for varicella (or
chickenpox) or other illnesses that can be prevented through vaccines, listeners can call
1-800-CDC INFO or visit the CDC immunization web site at cdc.gov/vaccines, where
they find more details about vaccine preventable diseases.

[Matthew Reynolds] Thank you for taking the time to talk with us today, Dr. Marin.

[Dr. Mona Marin] Thank you for having me, Matthew.

[Matthew Reynolds] That’s it for this week’s show. Don’t forget to join us next week.

Until then, be well. This is Matthew Reynolds for A Cup of Health with CDC.

[Announcer] To access the most accurate and relevant health information that affects you, your
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