Issue 1023: October 31, 2012

Ask the Experts: CDC Experts Answer Your Questions

All the questions and answers in this edition of IAC Express pertain to either new ACIP recommendations or reader questions. These Q&As first appeared in the October 2012 issue of Needle Tips.

IAC extends thanks to our experts, medical epidemiologist Andrew T. Kroger, MD, MPH; nurse educator Donna L. Weaver, RN, MN; and medical officer Iyabode Akinsanya-Beysolow, MD, MPH. All are with the National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention (CDC).

Questions and Answers
Q: Which formulations of influenza vaccines (i.e., nasal spray, intradermal, injectable high-dose, and injectable standard-dose) are recommend­ed for various age groups?

A: Six manufacturers are producing influenza vaccines for the U.S. market for the 2012–13 season. Influenza Vaccine Products for the 2012–2013 Influenza Season summarizes the vaccine products and age groups for which they are licensed.

Back to top

Q: Can a clinic vaccinate children younger than age 3 years with a 0.25 mL dose of influenza vaccine taken from a multi-dose vial of Fluzone (TIV; sanofi)? The multi-dose vial contains thimerosal as a preservative.

A: Yes. Fluzone is the only inactivated influenza vaccine licensed for use in children younger than age 3 years. It is available in single-dose and multi-dose vials. Multi-dose vials of Fluzone contain a small amount of thimerosal to prevent bacterial growth in the vials. Thimerosal-containing vaccines are safe to use in children. No scientific evidence indicates that thimerosal in vaccines causes adverse events unless the patient has a severe allergy to thimerosal.

However, a few states have enacted legislation that restricts the use of thimerosal-containing vaccines in children. To find out if your state has such restrictions, check with your state immunization program.

Back to top

Q: In recommending influenza vaccination for people age 65 and older, does CDC prefer that healthcare professionals administer high-dose influenza vaccine or standard-dose influenza vaccine?

A: CDC has no preference. CDC stresses that vaccination is the first and most important step in protecting against influenza.

Back to top

Q: If a patient received a dose of influenza vaccine in June (e.g., for international travel), how long should the patient wait before getting vaccinated with the next season’s flu vaccine?

A: There should be a minimum of 4 weeks between the doses in such situations.

Back to top

Q: Can adolescents and adults who have been exposed to pertussis be vaccinated if they haven’t had a one-time dose of Tdap yet?

A: Yes. Exposure to a person with pertussis is not a reason to avoid Tdap vaccination. All adolescents and adults who haven’t had a one-time dose of Tdap should receive a dose as soon as possible.

Back to top

Q: Should a person who received 2 doses of varicella vaccine be vaccinated with zoster vaccine when they turn 60?

A: No. CDC does not currently recommend zoster vaccine for people who received 2 doses of varicella vaccine. However, healthcare providers do not need to inquire about varicella vaccination history before administering zoster vaccine because virtually all people currently or soon to be in the recommended age group have not received varicella vaccine. For details, see page 19 of the CDC recommendations Prevention of Herpes Zoster.

Back to top

Q: Can we accept receipt of a single documented dose of zoster vaccine as proof of varicella immunity in a healthcare employee who has no other evidence of immunity?

A: No. Receipt of zoster vaccine is not proof of prior varicella disease. 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 physician diagnosis, (3) laboratory evidence of immunity, or (4) laboratory confirmation of disease. If a healthcare employee has already received a dose of zoster vaccine but has no evidence of immunity to varicella, the zoster dose can be considered the first dose of the 2-dose varicella series.

Back to top

Q: 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?

A: 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.

Back to top

Q: Does the recommendation to administer hepatitis B vaccine to diabetics younger than age 60 extend to women with gestational diabetes?

A: No. The 2011 CDC recommendations for hepatitis B vaccination of people with diabetes pertain to those with type-1 and type-2 diabetes. They do not apply to women with gestational diabetes. It is worth noting that pregnancy is not a contraindication to hepatitis B vaccination, and that women with gestational diabetes are more likely to develop type-1 or type-2 diabetes later in life. Diabetic women who become pregnant can be vaccinated, if indicated. See pages 1709-11 of the CDC recommendations Use of Hepatitis B Vaccination for Adults with Diabetes Mellitus.

Back to top

Q: I still am not clear about the need for testing if the hepatitis B vaccine series was completed many years ago—can you advise?

A: All healthcare personnel (HCP) with risk of exposure to hepatitis B should be tested 1–2 months after receiving the third dose of hepatitis B vaccine. CDC does not recommend testing healthcare personnel who were not tested within the 1–2 month postvaccination time frame. HCP who are exposed can be tested as part of postexposure management, if indicated. For more information, see Hepatitis B and Healthcare Personnel.

Back to top

Q: Should women who have not received HPV vaccine get Pap tests more often than women who have received HPV vaccine?

A: No. Receipt of HPV vaccine does not replace the need for cervical cancer screening. Women should consult their healthcare provider for recommendations regarding the frequency of cervical cancer screening, which includes Pap testing and HPV testing.

Back to top

Q: Is it acceptable practice to administer MMR, Tdap, and influenza vaccines to a postpartum mom at the same time as administering RhoGam?

A: Yes. Receipt of RhoGam is not a reason to delay vaccination. See page 9 of CDC’s General Recommendations on Immunization.

Back to top

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

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.

You can also email CDC's immunization experts directly at  There is no charge for this service.

If you have a question about IAC materials or services, email

Please forward these Ask the Experts Q&As to your co-workers and suggest they subscribe to IAC Express.

Back to top

About IZ Express

IZ Express is supported in part by Grant No. 1NH23IP922654 from CDC’s National Center for Immunization and Respiratory Diseases. Its contents are solely the responsibility of and do not necessarily represent the official views of CDC.

IZ Express Disclaimer
ISSN 2771-8085

Editorial Information

  • Editor-in-Chief
    Kelly L. Moore, MD, MPH
  • Managing Editor
    John D. Grabenstein, RPh, PhD
  • Associate Editor
    Sharon G. Humiston, MD, MPH
  • Writer/Publication Coordinator
    Taryn Chapman, MS
    Courtnay Londo, MA
  • Style and Copy Editor
    Marian Deegan, JD
  • Web Edition Managers
    Arkady Shakhnovich
    Jermaine Royes
  • Contributing Writer
    Laurel H. Wood, MPA
  • Technical Reviewer
    Kayla Ohlde

This page was updated on .