Read "Ask the Experts" Q&As on current immunization issues
Many readers of Needle Tips and Vaccinate Adults
consistently rank "Ask the Experts" as their favorite
feature in these publications. As a thank-you to our loyal
IAC Express readers, we periodically publish Extra Editions
with new "Ask the Experts" Q&As answered by CDC experts.
Back to top
IAC thanks William L. Atkinson, MD, MPH, and Andrew T.
Kroger, MD, MPH, medical epidemiologists at the National
Center for Immunization and Respiratory Diseases, CDC, for
agreeing to answer the following questions.
The Q&As in this edition of IAC Express deal with a variety
of current issues, with a special emphasis on Tdap vaccine
use due to the outbreaks of pertussis in some locations.
We encourage you to reprint any of these Q&As in your own
newsletters. Please credit the Immunization Action Coalition
and the Centers for Disease Control and Prevention.
Information about IAC's preferred citation style can be
found at http://www.immunize.org/citeiac
You can access more "Ask the Experts" Q&As in our online
archive at http://www.immunize.org/askexperts
Editor's note: Information about submitting a question to
"Ask the Experts" is provided at the end of this Extra
Q: When a vaccine vial is new and the cap has just been
removed, is the rubber stopper sterile, or should it be
cleansed with alcohol before inserting the needle?
A: The rubber stopper is not sterile. When you remove the
protective cap from a vaccine or diluent vial, you should
always clean the stopper with an alcohol wipe. This practice
is covered in CDC's online vaccine storage and handling
toolkit. To access the kit, go to
Q: I understand that a prior history of Guillain-Barré‚
syndrome (GBS) is no longer a precaution for giving
meningococcal conjugate vaccine (MCV4). Please tell me more
A: A history of GBS had previously been a precaution for
Menactra MCV4 vaccine (sanofi pasteur). Findings from two
studies that examined more than 2 million doses of Menactra
given since 2005 showed no evidence of an increased risk of
GBS. Consequently, ACIP voted in June 2010 to remove the
precaution for use of Menactra in people with a history of
GBS. This precaution did not apply to Menveo (Norvartis) or
Menomune (sanofi pasteur) vaccines.
Q: If a healthcare worker (HCW) receives tetanus-diphtheria-acellular pertussis (Tdap) vaccine and is then exposed to
someone with pertussis, do you treat the vaccinated HCW with
prophylactic antibiotics or consider them immune to pertussis?
A: You should follow the post-exposure prophylaxis protocol
for pertussis exposure recommended by CDC
Research is needed to evaluate the effectiveness of Tdap to
prevent pertussis in healthcare settings. Until studies
define the optimal management of exposed vaccinated
healthcare personnel, or experts arrive at consensus,
healthcare facilities should continue post-exposure
prophylaxis protocols for vaccinated HCWs who are exposed to
Q: As a pediatrician, I am concerned about protecting my
newborn patients from pertussis, especially given the recent
outbreak in California where 7 infants have died. How many
doses of pediatric diphtheria-tetanus-acellular pertussis
(DTaP) vaccine does an infant need before she or he is
protected from pertussis?
A: Vaccine efficacy is 80%-85% following 3 doses of DTaP
vaccine. Efficacy data following just 1 or 2 doses are
lacking but are likely lower. Therefore, it is especially
important that you advise parents of infants that all people
who live with the infant or who provide care to him or her
be protected against pertussis. Recommend that all the
infant's family members and visitors ages 10 through 64
years receive a one-time dose of adolescent/adult tetanus-diphtheria-acellular pertussis (Tdap) vaccine if they have
not already done so.
Q: Tdap vaccine is licensed for use only in people ages 10-64 years. Are there exceptions for healthcare professionals
or grandparents older than age 64 who are in contact with
A: ACIP has not recommended off-label use of Tdap for adults
age 65 years and older. However, there is no reason to
believe that Tdap is any less safe for people age 65 years
and older than it is for younger adults. Clinicians are
always free to use their clinical judgment; they may decide
that in this situation the benefit of administering Tdap
off-label exceeds any hypothetical risk of giving the
Q: We have a 16-year-old patient who received tetanus-diphtheria (Td) vaccine in the emergency room after a nail
puncture a year ago. Can we give him Tdap vaccine now?
A: No minimum interval is required between giving doses of
Td and Tdap to an adolescent who is or might be in contact
with an infant. This includes adolescents who are older
siblings of infants, babysitters, or hospital employees or
volunteers, etc. In circumstances like this, give Tdap
without delay. For adolescents who will not be in contact
with infants, CDC/ACIP recommends a routine wait of 5 years
between Td and Tdap administration unless a school
vaccination mandate requires giving Tdap.
Q: How would I follow up with a new healthcare worker (HCW)
who has 2 documented doses of measles-mumps-rubella (MMR)
vaccine but whose serologic testing doesn't show immunity to
one of these diseases?
A: Two documented doses of MMR vaccine is considered proof
of immunity according to ACIP. However, what ACIP recommends
is not always what schools and institutions accept. Here are
some basics about MMR vaccination and healthcare personnel.
- ACIP considers receipt of 2 documented doses of MMR
vaccine, given on or after the first birthday and separated
by at least 28 days, to be proof of immunity to measles,
mumps, and rubella. No serologic testing is required or
recommended to confirm immunity in this instance.
- If a HCW does not have any documented doses of MMR, he or
she can (1) be tested for immunity or (2) just be given 2
doses of MMR at least 4 weeks apart. If the testing option
is used, and the test indicates that the HCW is not immune
to one or more of the vaccine components, the HCW should
receive 2 doses of MMR at least 4 weeks apart. Note that a
test finding of an "indeterminate" or "equivocal" level of
immunity indicates that a HCW who lacks 2 documented doses
of MMR vaccine be considered nonimmune. Also note, that ACIP
does not recommend serologic testing after vaccination.
- ACIP does not routinely recommend more than 2 doses of MMR
vaccine. A negative serology after 2 documented doses
probably represents a false negative (i.e., antibody titer
is too low to detect with commercial tests). If a healthcare
setting relies on post-vaccination testing to determine
immunity, a negative serology can erroneously indicate that
a HCW needs additional doses. Remember, ACIP does not
recommend routine serologic testing after MMR vaccination.
For more information, see ACIP's recommendations on the use
of MMR at www.cdc.gov/mmwr/PDF/rr/rr4708.pdf
HOW TO SUBMIT A QUESTION TO "ASK THE EXPERTS"
IAC works with CDC to compile new "Ask the Experts" Q&As for
our publications based on commonly asked questions. We also
consider the need to provide information about new vaccines
and recommendations. Most of the questions are thus a
composite of several inquiries.
You can email your question about vaccines or immunization
to IAC at firstname.lastname@example.org As we receive hundreds of
emails each month, we cannot guarantee that we will print
your specific question in the "Ask the Experts" feature.
However, you will get an answer. To see if your question has
already been answered, you can first check the "Ask the
Experts" online archive at http://www.immunize.org/askexperts
You can also email CDC's immunization experts directly at
email@example.com There is no charge for this service.
If you have a question about IAC materials or services,
Please forward these "Ask the Experts" Q&As to your co-workers and suggest they subscribe to IAC Express at