| Varicella (chickenpox) |
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| Disease Issues |
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How serious a disease is varicella
(chickenpox)? |
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Prior to the availability of varicella vaccine
there were approximately 4 million cases of
varicella a year in the U.S. Though usually a
mild disease in healthy
children, an estimated 150,000 to 200,000
people developed complications, about 11,000
people required hospitalization and 100 people
died each year
from varicella. Varicella tends to be more
severe in infants, adolescents and adults than in young
children. The most common complications from
varicella include
bacterial superinfection of skin lesions,
pneumonia, central nervous system involvement,
and thrombocytopenia. |
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How is varicella transmitted and for how long
is an infected person contagious? |
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| The varicella
zoster virus (VZV) spreads from person to
person by direct contact or through the air by
coughing or sneezing. It is highly contagious.
It can
also be spread through direct contact with
fluid from a blister of a person infected with
varicella, or from direct contact with a skin
lesion from a person with
zoster (shingles). People with varicella are
infectious 1 to 2 days before skin lesions
appear until all lesions have crusted over,
usually 4 to 7 days after the
appearance of skin lesions. |
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| What can be
done to protect a patient without evidence of
immunity who is exposed to varicella and is at high risk for severe disease and
complications? |
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| ACIP recommends administration of varicella zoster immune globulin (VariZIG, Saol Therapeutics) to certain people up to 10 days following exposure to varicella or herpes zoster. People for whom VariZIG is recommended are those without evidence of immunity to varicella who are at high risk of severe disease and complications of varicella illness and are ineligible for varicella vaccination. VariZIG given up to 10 days after an exposure can modify or prevent clinical varicella disease. See the varicella zoster immune globulin section below, and www.cdc.gov/mmwr/pdf/wk/mm6228.pdf, pages 574–6, for more information on this topic. |
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| Patients recommended by ACIP to receive VariZIG include: |
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Immunocompromised patients without evidence of immunity |
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Newborn infants whose mothers have signs and symptoms of varicella around the time of delivery (i.e., 5 days before to 2 days after) |
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Hospitalized premature infants born at 28 weeks (or more) of gestation whose mothers do not have evidence of immunity to varicella |
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Hospitalized premature infants born at less than 28 weeks of gestation or who weigh 1,000 grams or less at birth, regardless of their mothers' evidence of immunity to varicella |
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Pregnant people without evidence of immunity |
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| If a susceptible person exposed to varicella or zoster is age 12 months or older, and has no contraindications to varicella vaccination, varicella vaccine can prevent or reduce the severity of infection when administered as post-exposure prophylaxis (PEP) as soon as possible, within 5 days after exposure. There is no evidence that vaccination after infection increases the risk of vaccine-associated adverse reactions. If the patient's exposure does not result in infection, vaccination can protect against future exposures. See the MMWR for details: www.cdc.gov/mmwr/preview/mmwrhtml/rr5604a1.htm. |
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| What do you
give to a child younger than 1 year of age if
they were exposed to the chickenpox or zoster
virus? |
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| The minimum age
for varicella vaccine is 12 months.
Vaccination is not recommended for infants
younger than 12 months of age even as
post-exposure
prophylaxis. CDC recommends that a healthy
infant should receive no specific treatment or
vaccination after exposure to VZV. The child
can be treated
with an appropriate antiviral medication if
chickenpox occurs. |
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| See the Varicella
Zoster Immune Globulin section below for
details on the recommended use of VariZIG in immunocompromised children, infants exposed
to varicella around the time of birth and some
hospitalized preterm infants. |
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| What varicella
vaccines are available in the United States? |
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| Two vaccines
containing varicella virus are licensed for
use in the United States. Both vaccines
contain live, attenuated varicella zoster
virus (VZV) derived
from the Oka strain. |
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Varivax (VAR, Merck) contains only
varicella vaccine virus. |
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ProQuad (MMRV, Merck) is a combination
measles, mumps, rubella, and varicella
vaccine. |
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| Both vaccines may be administered either by subcutaneous injection or intramuscular injection. VAR is
approved by the Food and Drug Administration (FDA) for people 12 months of age and
older. MMRV is approved for people 12 months
through 12 years of age. MMRV should not be
administered to people age 13 years or older. |
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| Who is
recommended to be vaccinated against
varicella? |
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| All children, beginning at age 12 months, as well as adults without other evidence of immunity should be vaccinated with 2 doses of varicella vaccine. Special consideration
should be given to vaccinating adults who (1)
have close contact with people at high risk
for severe disease (e.g.,
healthcare workers and family contacts of
immunocompromised people), or (2) are at high
risk for exposure or transmission (e.g.,
teachers of young
children; child care employees; residents and
staff members of institutional settings,
including correctional institutions; college
students; military personnel;
adolescents and adults living in households
with children; non-pregnant women of
childbearing age; and international
travelers). |
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| What are the
criteria for evidence of immunity to
varicella? |
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| The Advisory
Committee on Immunization Practices (ACIP)
considers evidence of immunity to varicella to
be: |
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Written documentation of 2 doses of
varicella vaccine given no earlier than
age 12 months with at least 4 weeks
between doses. |
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U.S.-born before 1980* |
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A
healthcare provider's diagnosis of
varicella or verification of history of
varicella disease |
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History of herpes zoster, based on healthcare provider diagnosis or verification of disease history |
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Laboratory
evidence of immunity or laboratory
confirmation of disease |
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*Note:
Although there is only a very small chance of susceptibility, due to the potential for severe consequences from varicella infection, year of birth is not accepted as evidence of varicella immunity for healthcare personnel, immunosuppressed people, and pregnant people. |
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| Does ACIP
recommend giving varicella vaccine to infants
before age 1 year if they are traveling internationally? |
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| No. ACIP
recommends giving a dose of MMR to infants age
6 through 11 months before international
travel, but not varicella vaccine. Varicella
vaccine is
neither approved nor recommended for children
younger than age 12 months in any situation. |
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| Can varicella
vaccine be used as postexposure prophylaxis
for a 9-month-old who was exposed to herpes
zoster? |
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| Varicella vaccine is neither approved nor recommended for children younger than age 12 months. Assuming that the child is not immunocompromised, varicella zoster immune globulin (VariZIG) is also not recommended. |
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| ACIP does not
have a recommendation for acyclovir for
varicella postexposure prophylaxis. The
American Academy of Pediatrics provide some
guidance
on this issue in the current edition of the Red Book. |
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| If a
healthcare worker does not have a history of
varicella vaccination or disease but has had a
clinically diagnosed case of shingles, does
she or he still
need varicella vaccination? |
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| No. A healthcare
provider's diagnosis or verification of a
history of shingles is acceptable evidence of
immunity to varicella. According to ACIP,
acceptable
evidence of varicella immunity in healthcare
personnel includes (1) documentation of 2
doses of varicella vaccine given at least 28
days apart, (2) history
of varicella or herpes zoster based on
clinician diagnosis, (3) laboratory evidence
of immunity, or (4) laboratory confirmation of
disease. |
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| I have a patient who is 52 years old and is immigrating to the U.S. She received a dose of recombinant zoster vaccine at age 50. The immigration requirements state she should receive 2 doses of varicella vaccine. Does she need additional varicella vaccine? |
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| Recombinant zoster vaccine (RZV, Shingrix, GSK) does not count as the first of two doses of varicella vaccine. Shingrix is not licensed and has not been evaluated for the prevention of primary varicella infection. To meet the immigration requirements, you should give a dose of varicella vaccine now and a second dose at least 4 weeks later. The varicella vaccine doses will not be harmful and will allow your patient to meet the regulatory requirement.
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| Concerning the
recommendation for a second dose of varicella
vaccine, does CDC recommend that a teen who
received only one varicella vaccine when
they were preschool age get a second dose now? |
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| Yes. For everyone whose varicella immunity is based on vaccination, 2 doses of varicella vaccine are recommended. |
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| Originally,
ACIP only recommended one dose of varicella
vaccine for children. Why did ACIP later
revise its recommendations to add a second
dose of
varicella vaccine for all children? |
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| In the ten years
following vaccine licensure in 1995, there was
a significant decline in varicella disease, as
well as varicella-related hospitalizations and
deaths. Although a 1-dose regimen was
estimated to be 80% to 85% effective,
breakthrough disease was still occurring in
highly vaccinated populations. A
2-dose regimen was adopted in 2006 to further
reduce the risk of disease among vaccinated
people whose numbers would accumulate over
time, which
could lead to varicella disease later in life
when it can be more severe. |
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| Should a child
who has had chickenpox prior to the first
birthday get the first dose of varicella
vaccine at age 1 year? |
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| If the child had
confirmed varicella disease or laboratory
evidence of prior disease, it is not necessary
to vaccinate regardless of age at infection.
If there
is any doubt that the illness was actually
varicella, the child should be vaccinated. |
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| How important
is it to vaccinate older children and adults? |
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| It is critical to
vaccinate susceptible older children and
adults whenever the opportunity arises. With
younger children being routinely vaccinated,
the
chance of being exposed to cases of chickenpox
is decreasing. Older children, adolescents,
and adults who have not had chickenpox now
have a greater
chance of remaining susceptible. These older
individuals, when they contract chickenpox,
are more likely to become seriously ill and have disease
complications than younger children. |
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| If an adult or
child has not had documented chickenpox but
has had shingles, is varicella vaccination recommended? |
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| No. Shingles is
caused by varicella zoster virus, the same
virus that causes chickenpox. A history of
shingles based on a healthcare provider
diagnosis is
evidence of immunity to chickenpox. A person
who has had shingles does not need to be
vaccinated against varicella. The person should still receive zoster vaccine, however, if it is not contraindicated and the person is age 50 or older or is age 19 or older and immunocompromised. |
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| Can we accept
receipt of a single documented dose of live
zoster vaccine as proof of varicella immunity
in a healthcare employee who has no other
evidence of immunity? |
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| No. Receipt of one dose of live zoster vaccine is not proof of varicella immunity. According to CDC, acceptable evidence of varicella immunity in healthcare personnel includes (1) documentation of 2 doses of varicella vaccine given at least 28 days apart, (2) history of varicella or herpes zoster based on clinician diagnosis, (3) laboratory evidence of immunity, or (4) laboratory confirmation of disease. If a healthcare employee has received a dose of live zoster vaccine in the past but has no other evidence of immunity to varicella, the live zoster dose can be considered the first dose of the 2-dose varicella series. Note that recombinant zoster vaccine (RZV, Shingrix) cannot be counted as the first dose in a 2-dose varicella vaccination series because Shingrix is not licensed and has not been evaluated for the prevention of primary varicella infection (chickenpox). |
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| Should a person who received 2 doses of varicella vaccine be vaccinated for herpes zoster with recombinant zoster vaccine, Shingrix, when they turn 50? |
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| Yes. In its 2018 recommendations for the prevention of herpes zoster, ACIP states that Shingrix may be used in adults age 50 years or older irrespective of prior receipt of varicella vaccine or live zoster vaccine (Zostavax, Merck). Shingrix is also recommended for adults age 19 and older who are immunocompromised due to disease or treatment if they have a history of varicella illness or vaccination. |
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| If a child has
a very mild case of chickenpox (for example,
only 5 to 10 pox), is s/he immune or should
s/he be vaccinated? |
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| A mild case of
chickenpox produces immunity to varicella as
does a moderate or severe case. A child with a reliable history of chickenpox does not need
to receive varicella vaccine. However, if
there is any doubt that the mild illness
really was chickenpox, it is best to vaccinate
the child. There is no harm in
vaccinating a child who is already immune. |
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| I understand
that varicella vaccine can be used in
postexposure settings. How soon after exposure
does the vaccine need to be administered? |
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| Varicella vaccine is most effective in preventing chickenpox or reducing the severity of the disease if used within 72 hours (3 days), and may still be helpful up to 5 days after exposure. However, not every exposure to varicella leads to infection, so for future immunity, varicella vaccine should be given to a person age 12 months or older who does not have a contraindication to vaccination, even if more than 5 days have passed since an exposure. |
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| A healthcare
worker with no history of chickenpox, and
unknown serologic immunity, was exposed to a patient with zoster. She received varicella
vaccine
two days later. She developed a pruritic
maculopapular rash 11 days after vaccination.
Is the rash from the vaccine or from her
zoster exposure? |
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| The only way to
determine whether the rash is caused by
wild-type varicella or vaccine virus is to try
to isolate virus from the rash and send it to
a
laboratory that is capable of differentiating
wild and vaccine-type virus. This is generally
not practical. Given the history, the
conservative approach is to
assume she has an active case of chickenpox
and act according to your infection control
guidelines. |
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| Does varicella
vaccine affect tuberculosis skin test readings
in the same way that MMR does? |
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| There is
currently no information on the effect of
varicella vaccine on reactivity to a
tuberculin skin test (TST). Until information
is available, it is prudent to
apply the same rules to varicella vaccine as
are applied to MMR: a TST (i.e., PPD) may be
applied before (preferably) or simultaneously
with varicella
vaccine. If vaccine has been given, delay the TST for at least 4 weeks. |
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| What are the
recommendations for varicella vaccination
before and after pregnancy? |
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| Live varicella vaccine should not be given to anyone known to be pregnant. If a person who is planning to become pregnant in the future comes in for a visit or an annual exam, the varicella history should be obtained and if indicated, 2 doses of vaccine should be given, spaced 4 to 8 weeks apart. Vaccine recipients capable of becoming pregnant should be counseled to avoid pregnancy for one month following each dose of varicella vaccine. A person who is inadvertently vaccinated while pregnant or becomes pregnant within a month of vaccination should be counseled about the theoretical risk to the fetus; however, it should not be considered a reason to terminate a pregnancy. Pregnant people should be assessed for evidence of varicella immunity and if non-immune, should receive the first dose of varicella vaccine following completion of the pregnancy and prior to hospital discharge. A second dose should be given 4 to 8 weeks later. |
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| Can a pregnant
healthcare worker with a history of varicella
infection care for a patient with varicella?
Is it possible for her to have a declining
titer, thus
making her susceptible to the virus again? |
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| People with a reliable history of varicella can be considered to be immune. A reliable history for healthcare personnel consists of (1) a healthcare provider's diagnosis of varicella or verification of history of varicella disease; (2) a healthcare provider's diagnosis of herpes zoster or verification of a history of herpes zoster; or (3) laboratory evidence of immunity or laboratory confirmation of disease. Immunity following disease or vaccination is probably life-long. More than one primary infection with varicella is unusual. |
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| Should serology screening for varicella be done during all pregnancies? |
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| No. Serologic testing for varicella should be considered only for pregnant people who do not have evidence of immunity (reliable history of chickenpox or documented vaccination). Once a person has been found to be seropositive, it is not necessary to test again in the future. |
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| How long should a person who has had varicella vaccination wait before becoming pregnant? |
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| Contrary to the
information provided in the vaccine package
insert, which states that pregnancy should be avoided for 3 months, the ACIP recommends
that a wait of 1 month is sufficient. |
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| If a person receives varicella vaccine and subsequently confirms pregnancy, what should the person be told about the risk to the fetus? |
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| To date, no
adverse outcomes of pregnancy or in a fetus
have been reported among people who
inadvertently received varicella vaccine
shortly before or
during pregnancy. The risk of congenital
varicella syndrome following varicella disease
is small, so the risk of congenital anomalies
following vaccination
with live attenuated varicella zoster virus (VZV)-containing
vaccine is probably very small. |
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| Merck and the
Centers for Disease Control and Prevention
(CDC) jointly operated a pregnancy registry
for women exposed to VZV-containing vaccines
for seventeen years after the licensure of
varicella vaccine. The registry was discontinued in 2013, having found no signals
to indicate a risk of Congenital
Varicella Syndrome or pattern of birth defects
related to vaccination with VZV-containing
vaccines. Healthcare providers may continue to
report exposure
to VZV-containing vaccines within 3 months of
conception or during pregnancy by contacting
Merck's call center at 1-877-888-4231. |
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| How has
widespread use of varicella vaccine in
children impacted disease? |
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| Substantial reductions in varicella morbidity and mortality have occurred following the licensure of vaccine. Between 1995 and 2019, reported cases of varicella fell more than 97% and hospitalizations fell by 90%; deaths fell by 89% and, among those younger than age 20, were practically eliminated (fell by 99.4%). There was no increase in herpes zoster, which had been considered as a potential side effect of the loss of natural boosting due to exposure. During this period, economists estimate that the childhood varicella vaccination program saved U.S. society about $23.4 billion. For more information, see the November 2022 Journal of Infectious Diseases special supplement about 25 years of the U.S. varicella vaccination program: https://academic.oup.com/jid/issue/226/Supplement_4. |
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| What is the
recommended schedule for vaccinating a child?
What about adults? |
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| For children, the
first dose should be given at age 12 months
with a second dose given at age 4 through 6
years. The second dose could be given earlier,
if necessary, as long as there is a 3-month (12-week) interval between doses. Although a 3-month minimum interval is recommended in children younger than age 13, the second dose does not need to be repeated if separated from the first dose by a shorter interval of at least 4 weeks. |
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| All children age 13 years and older as well as adults without evidence of immunity should also have documentation of 2 doses of varicella vaccine, separated by a minimum interval of 4 weeks. |
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| Some children
in my practice have had only 1 dose of
varicella vaccine. Is there a problem waiting
until the 11- to 12-year-old visit to give
them the second
dose? |
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| Don't delay
giving the second dose of varicella vaccine.
Give the second dose the next time the child
is in your office. The recommendation to
routinely
give a second dose at age 4 through 6 years is
intended to provide improved protection in the
15% to 20% of children who do not adequately
respond to
the first dose. |
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| In what
circumstances should I obtain a varicella
titer after vaccination? |
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| Postvaccination
serologic testing for varicella immunity is not recommended in any
group, including healthcare personnel. |
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| A child
received only one dose of varicella vaccine
and subsequently tests positive for varicella
IgG antibody. Does the child still need a
second dose of
varicella vaccine? |
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| Varicella postvaccination serologic testing is not recommended; however, if a person tests positive for varicella antibody 28 days or more after vaccination, the Advisory Committee on Immunization Practices (ACIP) considers the person to be immune. CDC prefers that the child receive a second dose to assure long-term immunity, but doing so is not absolutely necessary. You can access the ACIP varicella vaccine recommendations, which include evidence of immunity (page 16) at www.cdc.gov/mmwr/pdf/rr/rr5604.pdf. |
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| Should I test pregnant people for varicella immunity at the first prenatal visit? |
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| Test pregnant people who lack either (1) documentation of receipt of 2 doses of varicella vaccine or (2) healthcare provider diagnosis or verification of varicella or herpes zoster disease. Those who are not immune should begin the 2-dose vaccination series immediately postpartum. |
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| What is the
appropriate lab test to use to determine
whether there has been previous chickenpox
disease? |
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| Commercially
available laboratory tests for varicella
antibody are usually based on a technique
called EIA (enzyme immunoassay). Though these
tests are
sufficiently sensitive to detect antibody
resulting from varicella zoster virus
infection, they are generally not sensitive
enough to detect vaccine-induced
antibody. The more sensitive assays needed to
detect vaccine-induced antibody are not widely
available. This is why CDC does not recommend
antibody
testing after varicella vaccination. |
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| I work in
employee health. Several hospital employees
have told me they have had chickenpox, but
their titers show no antibodies. Should I
offer varicella
vaccination to them even though they insist
they've had the illness? |
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| If you cannot
verify a healthcare employee's history of
chickenpox, the employee should receive 2
doses of varicella vaccine at least 4 weeks
apart. For
details, refer to pages 16 and 26 of the CDC
recommendations Prevention of Varicella at
www.cdc.gov/mmwr/pdf/rr/rr5604.pdf. |
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| A nursing
student received 2 valid, documented doses of
varicella vaccine. For whatever reason, she subsequently had a titer drawn. The titer was
negative. Do you recommend revaccination with
2 doses of varicella vaccine? |
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| No. Documented
receipt of 2 doses of varicella vaccine
supersedes results of subsequent serologic
testing. Most commercially available tests for
varicella
antibody are not sensitive enough to detect
vaccine-induced antibody, which is why CDC
does not recommend post-vaccination testing.
For more
information, see page 24 of ACIP's
Immunization of Health-Care Personnel,
available at
www.cdc.gov/mmwr/pdf/rr/rr6007.pdf. |
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| A child in our
practice received her first dose of varicella
vaccine when she was 12 months old and her second dose when she was 14 months old. The
second dose was only 2 months after the first.
Is the second dose valid or does it need to be
repeated? |
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| The recommended minimum interval between two doses of varicella vaccine for children 12 months through 12 years of age is 12 weeks. However, the second dose of varicella vaccine does not need to be repeated if records show it was separated from the first dose by at least 4 weeks. See www.cdc.gov/vaccines/hcp/acip-recs/general-recs/timing.html, Table 3-2. |
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| What are the contraindications and precautions to varicella vaccine? |
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| Contraindications: |
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History of a serious allergic reaction (e.g., anaphylaxis) after a previous dose of varicella vaccine or to a varicella vaccine component. For information on vaccine components, refer to the manufacturer's package insert (www.immunize.org/fda) or go to www.cdc.gov/vaccines/pubs/pinkbook/downloads/appendices/B/excipient-table-2.pdf. |
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Pregnancy |
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Severe immunodeficiency (e.g., from hematologic and solid tumors, receipt of chemotherapy, congenital immunodeficiency, long-term immunosuppressive therapy [e.g., two weeks or more of daily receipt of 20 mg or more, or 2 mg/kg body weight or more, of prednisone or equivalent] or patients with HIV infection who are severely immunocompromised [a child age 1 through 5 years with CD4+ T-lymphocyte percentage less than 15% or a person age 6 years or older with a CD4+ T-lymphocyte count less than 200 cells per microliter]) |
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Family history of congenital or hereditary immunodeficiency in first-degree relatives (e.g., parents, siblings) unless the immune competence of the potential vaccine recipient has been clinically substantiated or verified by a laboratory |
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| Precautions: |
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Recent receipt (within the previous 11 months) of antibody-containing blood product (specific interval depends on product) |
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Moderate or severe acute illness with or without fever (defer until recovery) |
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Use of aspirin or aspirin-containing products |
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Receipt of specific antiviral drugs (acyclovir, famciclovir, or valacyclovir) 24 hours before vaccination (avoid use of these antiviral drugs for 14 days after vaccination) |
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| Precautions for combination MMRV (ProQuad, Merck) only (approved for children 1 through 12 years of age) also include: history of thrombocytopenia or thrombocytopenic purpura, a personal or family history of seizures of any etiology, and a need for tuberculin skin testing or interferon-gamma release assay (IGRA) testing. |
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| For additional information, see the General Best Practice Guidelines for Immunization section on contraindications and precautions, table 4–1 and associated footnotes, at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/contraindications.html or consult Immunize.org's "Guide to Contraindications and Precautions to Commonly Used Vaccines" at www.immunize.org/catg.d/p3072a.pdf. |
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| What are the
recommendations for the use of varicella
vaccine in children with HIV or other immunodeficiencies? |
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| The CDC General
Best Practice Guidelines for Immunization
section on altered immunocompetence recommends varicella vaccination of children with
humoral (but not cellular) immunodeficiencies.
In addition, single-antigen varicella vaccine
should be considered for HIV-infected children
age 1 through 5
years with CD4+ T-lymphocyte percentages
greater than or equal to 15% for at least 6
months or for children age 6 years and older
with CD4+ T-lymphocytes count greater than or equal to 200
cells per microliter for at least 6 months.
Eligible children should receive 2 doses of
varicella vaccine with a
3-month interval between doses. Additional
details of these recommendations can be found
in table 8-1 and associated footnotes at
www.cdc.gov/vaccines/hcp/acip-recs/general-recs/immunocompetence.html. |
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| We have a 40
lb six-year-old patient who has been taking 15
mg of methotrexate weekly for arthritis for 12
months. Can we give the child MMR and
varicella vaccine based on this methotrexate
dosage? |
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| Based on the
weight and dosage provided (40 lbs and 15
mg/week), the child is currently receiving
more than 0.4 mg/kg/week of methotrexate. This
meets the Infectious Disease Society of
America (IDSA) definition of high-level
immunosuppression. Administration of both
varicella and MMR vaccines are contraindicated
until such time as the methotrexate dosage can
be reduced. The 2013 IDSA definition of
low-level immunosuppression for methotrexate
is a dosage of less than 0.4 mg/kg/week. For
additional details, see the 2013 IDSA Clinical
Practice Guideline for Vaccination of the
Immunocompromised Host:
cid.oxfordjournals.org/content/early/2013/11/26/cid.cit684.full.pdf. |
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| As a general rule, whenever feasible, it is recommended that non-live and live vaccines be administered 2 or more weeks before initiating immunosuppressive medications include human immune mediators like interleukins and colony-stimulating factors, immune modulators, and medicines like tumor necrosis factor-alpha inhibitors and anti-B cell agents. See CDC General Best Practice Guidelines for Immunization section on altered immunocompetence: www.cdc.gov/vaccines/hcp/acip-recs/general-recs/immunocompetence.html. |
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| I had an
18-year-old in the clinic today for varicella
vaccination. He reports having
antiphospholipid syndrome being treated with
rituximab (a drug that
affects the function of lymphocytes). The next
dose of rituximab will be in 2 weeks. He has
also had 12 immune globulin (IG) injections in
the last year.
Should he get the varicella vaccine at all
with this condition, and if so, what time
frame do we need to be concerned with in
relation to the rituximab
treatment and/or IG? |
|
| The IDSA
guidelines indicate that persons receiving
rituximab should be considered to have
high-level immunosuppression. Both inactivated
and live
vaccines should be withheld at least 6 months
following treatment with lymphocyte depleting
medications such as rituximab. As for the IG,
the interval to live
vaccination depends on the dose. For guidance, please refer to the Timing and Spacing of Immunobiologics section of CDC's General Best Practices Guidelines for Immunization, table 3–6: "Recommended intervals between administration of antibody-containing products and measles- or varicella-containing vaccine, by product and indication for vaccination" at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/timing.html. This interval could be as long as 11 months, depending on the dose he receives. |
|
| Recently we
had a one-year-old with congenital heart
disease and who is on chronic aspirin therapy
in for a well-child check and routine
vaccination. Are
there any recommendations regarding varicella
vaccine being given to children who are on
chronic aspirin therapy? |
|
| The ACIP's
varicella vaccine recommendations state that
no adverse events associated with the use of
salicylates after varicella vaccination have
been
reported, however, the vaccine manufacturer
recommends that vaccine recipients avoid using salicylates for 6 weeks after receiving
varicella vaccines
because of the association between aspirin use
and Reye syndrome after varicella disease
(chickenpox). Vaccination with subsequent
close monitoring
should be considered for children who have
rheumatoid arthritis or other conditions
requiring therapeutic aspirin. The risk for
serious complications
associated with aspirin is likely to be
greater in children in whom natural varicella
develops than it is in children who receive
the vaccine containing
attenuated varicella zoster virus. In other
words, the benefit of varicella vaccine likely
outweighs the theoretical risk of Reye
syndrome. See the ACIP
varicella recommendations at
www.cdc.gov/mmwr/PDF/rr/rr5604.pdf,
page 29. |
|
| After
receiving varicella vaccine, should healthcare
personnel avoid contact with immunocompromised patients? |
|
| This is not
necessary unless the person who was vaccinated
develops a rash. |
|
| Is there any
concern when giving varicella vaccine to a
child who lives with a susceptible pregnant woman or an immunocompromised individual? |
|
| ACIP recommends
varicella vaccine for healthy household
contacts of pregnant people and
immunosuppressed people. Although there may be
a small
risk of transmission of varicella vaccine
virus to household contacts, the risk is much
greater that the susceptible child will be
infected with wild-type
varicella, which could present a more serious
threat to household contacts. |
|
| A pediatric
surgeon's 12-month-old child received the
varicella vaccine and two weeks later
developed a varicella-like rash. The surgeon
had chickenpox
as a child and had a positive varicella titer
several years ago. Is it okay for the surgeon
to continue to see patients? Also, is the
varicella virus in the rash
that develops following vaccination as
virulent as the wild-type virus? |
|
| Because the
surgeon is immune, the child's rash is not a
problem and there is no need for the surgeon
to restrict activity. In comparing a vaccine
rash to
wild-type chickenpox infection, transmission
is less likely with a vaccine rash and, in
general, there are fewer skin lesions. |
|
| If a patient
is breast-feeding her six-month-old baby, can
she receive varicella vaccine without the risk
of transmitting the vaccine virus to her baby? |
|
| There has been
only one published report of mother to child
transmission of varicella vaccine virus. If
the susceptible woman were to be infected with
wild
varicella virus, the risk of transmission to
the infant would be much higher. Breastfeeding
is not a contraindication or a precaution to
varicella vaccination
of the mother when vaccination is indicated. |
|
| A 10-year-old
girl came to our immunization clinic, and the
nurse noted crusted lesions on her arms and legs. The parent said the child had had
chickenpox a week earlier. The girl was not
ill, so we vaccinated her. But now I wonder if
her recent case of chickenpox might interfere
with her immune
response to vaccines. |
|
| A previous
history of chickenpox disease, even recent
disease, is not known to interfere with the
immune response to different vaccines. To
review the true
contraindications and precautions to
vaccination, consult Immunize.org's "Guide to Contraindications and Precautions to Commonly
Used Vaccines" at
www.immunize.org/catg.d/p3072a.pdf. |
|
| Another helpful
resource is CDC's General Best Practice
Guidelines for Immunization. It contains a
useful table titled "Conditions incorrectly
perceived as
contraindications or precautions to
vaccination (i.e., vaccines may be given under
these conditions)". The table is available at
www.cdc.gov/vaccines/hcp/acip-recs/general-recs/contraindications.html,
Table 4-2. |
|
| We have a
patient who has selective IgA deficiency. We
also have patients with selective IgM
deficiency. Can MMR or varicella vaccine be
administered to
these patients? |
|
| There is no known
risk associated with MMR or varicella
vaccination in someone with selective IgA or
IgM deficiency. It is possible that the immune
response may be weaker, but the vaccines are
likely effective. |
|
|
|
|
|
| How safe is
varicella vaccine? |
|
| Varicella vaccine
is very safe. About 20% of vaccine recipients
will have minor injection site complaints,
such as pain, swelling, or redness. Fewer than
5%
of recipients develop a localized or
generalized varicella-like rash 5 to 26 days
after vaccination. These rashes have an
average of 2 to 5 lesions, and may
be maculopapular rather than vesicular. Fever
following varicella vaccine is uncommon. |
|
| If a child had
1 varicella vaccination and developed a
vesicular (chickenpox-like) rash at the
vaccination site 7 to 10 days after
vaccination, does the
patient still need the second dose? What if
the rash covered the entire body? |
|
| If you believe
the child had varicella disease (that is,
breakthrough varicella) after the first dose,
the child does not need another dose. If you
are uncertain
whether the child had varicella or a rash related to varicella vaccination, the second
dose should be administered on schedule. If in
doubt, give the second dose. If this was a
case of breakthrough
varicella, a second dose will not be harmful. |
|
| If a child
breaks out in 5 to 10 maculopapular spots 2
weeks following varicella vaccination, can
s/he go to school? |
|
| Transmission of
varicella vaccine virus is a rare event, and
appears to occur only when the vaccinated
person develops a vesicular rash. A maculopapular
rash 2 weeks after varicella vaccine may not
have been caused by the vaccine. If the rash
were caused by the vaccine, the risk of
transmission is very
small; however, the child should avoid close
contact with people who do not have evidence
of varicella immunity and who are at high risk
of complications
of varicella, such as immunocompromised
people, until the rash has resolved. |
|
| If a
vaccinated child gets 5 to 10 vesicular
lesions 2 weeks after vaccination, can s/he
attend school? |
|
| You cannot
distinguish a mild case of varicella disease
from a rash caused by the vaccine. The child
may have been infected with varicella at about
the
same time s/he was vaccinated. The
conservative approach would be to treat the
child as if s/he had chickenpox and restrict
her/his activities until all the
lesions crust. |
|
| If a child
gets breakthrough varicella infection, about
50 lesions, can s/he go to school? |
|
| Breakthrough
varicella represents replication of wild
varicella virus in a vaccinated person.
Although most breakthrough disease is very
mild, the child is
contagious and activities should be restricted
to the same extent as an unvaccinated person
with varicella disease. |
|
| Can a young
child, who was recently vaccinated for
chickenpox, spread the vaccine virus to other household members? |
|
| Available data
suggest that healthy children are unlikely to
transmit vaccine virus. Transmission of
vaccine virus to a household contact has
rarely been
documented. It appears that transmission of
vaccine virus occurs mostly, or perhaps even
exclusively, when the vaccinated person
develops a rash following
vaccination. |
|
| If a person
develops a rash after receiving varicella
vaccination, does he need to be isolated from susceptible people who are either pregnant or
immunosuppressed? |
|
| Transmission of
varicella vaccine virus is rare. However, if a
pregnant or immunosuppressed household contact
of a vaccinated person is known to be
susceptible to varicella, and if the vaccinee
develops a rash 7 to 21 days following
vaccination, it is prudent that they avoid
prolonged close contact with the
susceptible person until the rash resolves. |
|
| An 8-month-old
was erroneously given varicella vaccine. What
might the consequences be? What should we do
now? |
|
| An 8-month-old is
likely to have residual passive varicella
antibody from his or her mother. The vaccine
probably will have no effect, and no action is
necessary. The dose should not be counted, and
the child should be revaccinated on schedule
at 12 through 15 months of age. |
|
|
|
|
|
| What is
varicella zoster immune globulin? |
|
| Varicella zoster
immune globulin (VariZIG, Saol Therapeutics)
is a human blood product prepared from plasma obtained from healthy, volunteer blood
donors identified by routine screening to have
high antibody titers to varicella-zoster
virus. The first varicella zoster immune
globulin, VZIG, became
available in 1978. In a study of immunocompromised children who were
administered VZIG within 96 hours of exposure,
approximately one in five exposed
children developed clinical varicella, and one
in 20 developed subclinical disease compared
with 65%—85% attack rates among historical
controls. In
2006, VZIG was discontinued and a new product,
VariZIG, became available. |
|
| What groups of
patients are eligible for VariZIG? |
|
| Varicella zoster immune globulin, VariZIG (Saol Therapeutics), is
recommended for patients without evidence of
immunity to varicella who are at high risk for
severe varicella and complications, who have
been
exposed to varicella or herpes zoster, and for
whom varicella vaccine is contraindicated.
Patient groups recommended by CDC to receive VariZIG include
the following: |
|
| • |
|
Immunocompromised patients without
evidence of immunity |
|
|
|
| • |
|
Newborn infants whose mothers have signs
and symptoms of varicella around the
time of delivery (i.e., 5 days before to
2 days after) |
|
|
|
| • |
|
Hospitalized preterm infants born at 28
weeks or more of gestation whose mothers
do not have evidence of immunity to
varicella |
|
|
|
| • |
|
Hospitalized preterm infants born at
less than 28 weeks of gestation or who
weigh 1,000 grams or less at birth, regardless of their mothers'
evidence of immunity to varicella |
|
|
|
| • |
|
Pregnant people without evidence of
immunity |
|
|
| CDC recommends administration of VariZIG as soon as possible after exposure to varicella-zoster virus, ideally within 96 hours, but not beyond 10 days after exposure. The most recent recommendations for the use of VariZIG were published in 2013 and are available at www.cdc.gov/mmwr/pdf/wk/mm6228.pdf on pages 574–576. |
|
| What is the
recommended dosage of VariZIG? |
|
| Varicella zoster immune globulin, VariZIG (Saol Therapeutics), is supplied in 125-IU vials and should be administered intramuscularly as directed by the manufacturer. The recommended dose is 125 IU/10 kg of body weight, up to a maximum of 625 IU (five vials). The minimum dose is 62.5 IU (0.5 vial) for patients weighing 2.0 kg or less and 125 IU (one vial) for patients weighing 2.1–10.0 kg. For ordering information see varizig.com/liquid-product_info.html. |
|
| A
one-month-old infant was exposed for the last
6 days to chickenpox. What should be done to
protect the exposed infant, who is too young
to vaccinate? |
|
| There
is no evidence that healthy full-term infants
born to women in whom varicella occurs more
than 48 hours after delivery are at increased
risk for
serious complications such as pneumonia or
death. Varicella zoster immune globulin, VariZIG, can be given up to 10 days after
exposure but is only
recommended for newborn infants whose mothers
have signs and symptoms of varicella around
the time of delivery (5 days before to 2 days
after),
hospitalized premature infants born at 28 or
more weeks of gestation whose mothers do not
have evidence of immunity to varicella, or
hospitalized
premature infants born at less than 28 weeks
of gestation or who weigh 1,000 grams or less
at birth regardless of their mothers' evidence
of immunity to
varicella. Assuming this is an infant at home, VariZIG would not be recommended. Varicella,
if it develops, would be managed as for any
child. |
|
|
|
|
|
| How should
varicella vaccine be stored in my clinic? |
|
| Live varicella-containing vaccines (varicella, MMRV) must be stored in a freezer at a temperature between -50°C and -15°C (between -58°F and +5°F) until reconstitution and administration. These vaccines can deteriorate rapidly after they are removed from the freezer. A separate stand-alone freezer or a combination refrigerator-freezer purpose-built for vaccine storage (sometimes called "pharmaceutical grade") should be used to store frozen vaccines that require storage temperatures between -50°C and -15°C (between -58°F and +5°F). A stand-alone storage unit that is frost-free or has an automatic defrost cycle is preferred. Frozen vaccines should not be stored in the freezer compartment of a household-type combination unit because household freezers in combination units cannot reliably maintain proper storage temperatures for frozen vaccines. This applies to both temporary and long-term storage of frozen vaccines. The diluents should be kept separately in the refrigerator or at room temperature. Live varicella-containing vaccines must be administered within 30 minutes of reconstitution. |
|
| What happens
if you put varicella vaccine in the
refrigerator instead of the freezer? |
|
| Vaccine may lose potency rapidly if not stored according to the manufacturer's instructions. However, it may still be permissible to use vaccine that has not been properly stored. Put the affected vaccine
vials into the freezer after you have marked
them so they are not confused with the
unaffected vials, then call the
manufacturer at 1-800-9-VARIVAX
(1-800-982-7482) for further guidance about
whether the vaccine is still usable.
Unreconstituted varicella vaccine may
be stored in the refrigerator for up to 72
hours before use. If refrigerated varicella
vaccine is not used within 72 hours, it should
be discarded. |
|
|
If you have inadvertently left your vaccine at
room temperature instead of in the freezer or
have experienced a power failure, label the
affected vaccine to
keep it separated from unaffected vaccine and
return it to recommended storage conditions in
a freezer promptly, then contact the
manufacturer for
further guidance. Do not administer the
vaccine until you have consulted with Merck. |
|
| How can I
transport varicella vaccine? What if I do not
have access to a portable freezer? |
|
| The vaccine
manufacturer does not recommend transporting
varicella-containing vaccines (varicella,
MMRV). If these vaccines must be transported
(for example during an emergency), CDC
recommends use of a portable vaccine freezer
unit or qualified container and packout that
maintains temperatures between -50°C and -15°C
(- 8°F and +5°F). Do not use dry ice, even for temporary storage. Dry ice might expose the vaccines to temperatures colder than -50°C (-58°F), resulting in compromise of the vial stopper material. |
|
|
Follow these steps for transporting frozen
vaccines: |
|
| • |
|
Place a temperature monitoring device
(preferably with a buffered probe) in
the container as close as possible to
the vaccines. |
|
|
|
| • |
|
Immediately upon arrival at the destination, unpack the vaccines and place them in a freezer at a temperature range between -50°C and -15°C (-58°F and +5°F). Any stand-alone freezer or freezer purpose-built for vaccine storage that maintains these temperatures is acceptable. |
|
|
|
| • |
|
Record the
time vaccines are removed from the
storage unit and placed in the transport
container, the temperature during
transport,
and the time at the end of transport
when vaccines are placed in a stable storage unit. |
|
|
| If necessary,
varicella-containing vaccines may be
transported or stored at refrigerator
temperature between 2°C and 8°C (between 36°F
and 46°F) for up
to 72 continuous hours prior to
reconstitution. To do so, follow the steps above using a portable vaccine refrigerator
unit or a qualified container and
packout designed to maintain vaccine storage
temperatures between 2°C and 8°C (between 36°F
and 46°F). |
|
| Transport of
varicella-containing vaccine at temperatures
other than the recommended range between -50°C
and -15°C (-58°F and +5°F) is considered a
temperature excursion, so contact Merck at
(800) 982-7482 for further guidance. Do not
discard vaccines without contacting the
manufacturer and/or
your immunization program for guidance. |
|
| For additional
guidance, see the CDC Vaccine Storage and
Handling Toolkit at
www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf. |
|
| I was told by
a coworker that varicella vaccine can be
stored at refrigerator temperature for up to
three days and still be used. Is this true? |
|
| Yes. According to
the manufacturer, unreconstituted varicella
vaccine may be stored at refrigerator
temperature (2°C to 8°C, 36°F to 46°F) for up
to 72
continuous hours prior to reconstitution.
Vaccine stored at 2°C to 8°C that is not used
within 72 hours of removal from -15°C (+5°F)
storage should be
discarded. See
www.merck.com/product/usa/pi_circulars/v/varivax/varivax_pi.pdf. |
|
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ACIP Recommendations
Vaccine Information Statements 
