Ask the Experts, a long-standing and ever-popular feature of the Immunization Action Coalition’s (IAC) website for healthcare professionals, has been one of the most highly visited destinations on since IAC’s website was launched in 1994. For more than 20 years, vaccine experts from CDC’s National Center for Immunization and Respiratory Diseases have been working closely with IAC to answer questions about the use of vaccines that come up every day in medical practices across the United States.

Over the years, IAC has published these Q&As in Needle Tips, our quarterly flagship publication for healthcare professionals, as well as in Vaccinate Adults, an abbreviated version of Needle Tips for adult medicine specialists. The Q&As also appear in every issue of IAC Express, our free email news and information service which is sent out every Wednesday to more than 50,000 healthcare professionals.

Whether you are looking for answers to questions about dosing intervals when a patient has fallen behind schedule, what to do when a vaccine is given too early, or which influenza vaccine is most appropriate to use for a particular patient, you’ll likely find what you’re looking for at

Here are some of the most popular Ask the Experts Web pages:

To receive Ask the Experts Q&A answered by CDC experts every Wednesday, subscribe to IAC Express.

Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel.