Wednesday, August 12, 2009

What did flu vaccine experts talk about before the swine flu pandemic occurred?

DHHS's National Vaccine Advisory Committee (NVAC) met February 5-6, 2009. Here is a section of the NVAC minutes that dealt with the concept of vaccinating the public for a "Bird Flu" H5N1 pandemic--vaccinating before an epidemic appeared.  Remember that Bird Flu, though deadly, has not spread from one person to another, but only from a small number of birds to a small number of people--and stopped there.

However, US flu experts had already decided that they could employ an "Emergency Use Authorization" for Bird Flu vaccine.  The way the law is written (Section 564 of the Food, Drug and Cosmetic Act) allows an emergency use authorization to be invoked for any potential emergency, broadening the scope of how this law can be used considerably.  The Secretary of Health and Human Services makes the declaration after confirmation of the emergency/potential emergency by the Secretary of Homeland Security or Secretary of Defense, or without consultation if it is deemed there is a threat to national security.  Then unlicensed drugs, vaccines and devices can legally be used for the emergency or potential emergency.

In this way, an unlicensed Bird Flu vaccine with novel adjuvants could be used for the American public, pandemic or no, based on the hope that it might provide some future immunity were bird flu to appear.  Here are the minutes of the discussion (I have added the bold type):

Pre-pandemic Vaccination Policy - Andrew T. Pavia, M.D.

Dr. Pavia said NBSB is evaluating the prospect of pre-pandemic use of pandemic influenza vaccine, which is being considered in other countries. The WHO's SAGE is performing a comprehensive review of the topic and will meet to discuss it in April.

Pre-pandemic vaccination involves using H5 or some other vaccine to prevent a potential pandemic before a true pandemic outbreak occurs. The United States has a stockpile of pre-pandemic vaccine that, until recently, offered narrow protection and had limited uses. The development of novel adjuvants has dramatically altered the potential uses of the existing vaccine. Large, phase-III studies are still needed, but consistent evidence has shown three different adjuvants to be effective. The adjuvants allow use of much less vaccine to achieve the same immunogenicity and, more importantly, may induce broad, cross-neutralizing antibodies. Evidence suggests that a perfect vaccine match is not needed to ensure protection. In addition, the adjuvants may act as primers; that is, while the first or second vaccine dose may be a poor match, the use of adjuvants may improve the response to a later, better-matched vaccine.

Dr. Pavia said NBSB (of which he is a member) was asked by the BARDA and ASPR to evaluate the policy implications of pre-pandemic vaccination. Dr. Pavia said NBSB first seeks to define who should be represented in the subgroup evaluating pre-pandemic vaccine. Dr. Pavia emphasized the need for input from people with experience in past episodes involving complex public-health decision-making. The makeup of the subgroup and format of the meetings remain to be determined, and Dr. Pavia stressed that the issues are politically sensitive.


Dr. Birkhead pointed out that the novel adjuvants are not yet licensed in the United States and wondered whether they would require an investigative new drug application process. Dr. Pavia said one option is to declare an emergency for specific groups and use the adjuvants under an FDA emergency use authorization. Dr. Baylor said FDA is discussing the issue with its counterparts around the world. He believes that data from ongoing research by influenza vaccine manufacturers will drive the process, but the decision to pursue pre-pandemic vaccine should be a global one. Dr. Gellin (CDC) said the United States has the vaccine in its stockpile; the question is whether the benefits of using it for pre-pandemic vaccination outweigh the risks. Dr. Baylor (FDA) countered that the decision should be based on data, not the availability of vaccine in the stockpile. Dr. Pavia said in the United States, decision-making has not reached that level.

Dr. Salisbury described the WHO virtual stockpile of H5N1 vaccine and said the SAGE meeting is intended to address the best uses of the stockpile. Dr. Pavia emphasized that the biggest challenge is grappling with the issue of using a non-licensed vaccine for a disease that does not yet exist.

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