Provider FAQ


Influenza Vaccine Production and Distribution

  • What is "proportional distribution"?
    The CDC recommends that proportional distribution is only used when a shortage or delay in the vaccine supply occurs to ensure that high-risk populations receive priority access to vaccine. In the event of any future vaccine shortages or delays, suppliers will distribute a corresponding ‘proportion’ of their total received supply to the broadest possible provider base.


  • Shouldn’t all vaccination be done in medical care facilities like doctors’ offices, hospitals and community clinics?
    More flu shots are given in the doctor’s office (approximately 48%) than any other single setting. The second highest setting for a flu shot is the workplace (20%). For some patients, convenience does play a role in the decision to get a flu shot.  With a U.S. population of approximately 300 million, and with the CDC currently recommending that flu shots be given to more than 85% of Americans, widely available flu vaccine is essential. Workplace or retail centers offer access and convenience, removing real or perceived barriers that may prevent some patients from getting their flu shot.


  • Why doesn’t the CDC just stockpile flu vaccine?
    A stockpile developed early in the season would remove doses from circulation during the most critical and optimal period for vaccine administration and when demand is the highest. Also, because flu strains change each year, the vaccine is only good for the flu season for which it’s produced. Leftover supplies of flu vaccine are destroyed.


  • Why do we continue to experience disruptions to the influenza vaccine supply?
    Flu vaccine is made using a sensitive manufacturing process and there are just five manufacturers producing for the U.S. market. The vaccine contains multiple strains of vaccine and each strain is grown in millions of chicken eggs. Then the strains are combined into a single vaccine, must pass manufacturing efficacy testing and must be certified by the FDA before being released for sale.The manufacturers producing for the U.S. market must run their facilities at maximum capacity to meet the U.S. demand. Production problems at any one of the companies can have substantial impact on supply and/or the timing of its delivery. To counter this, manufacturers are expanding or adding new production facilities and distributors are making new commitments to distribute larger amounts of vaccine. Also the federal government has provided substantial research grants to develop synthetic vaccine.


  • How can communications about influenza vaccine supply and distribution be improved?
    The CDC is collecting, and will disseminate, data that will give all flu vaccine stakeholders more transparency into the totality of the process. In addition, increased cooperation between the major manufacturers and distributors is occurring. All flu vaccine stakeholders should have more information on the progress in manufacturing the vaccine; projections of total production; methods of pre-booking vaccine and determining how it is divided between various categories of providers; and the timing of vaccine distribution.


  • Why doesn’t the CDC recommend that all persons in the U.S. receive influenza vaccine annually? Why is demand for flu shots increasing?
    The Centers for Disease Control & Prevention (CDC) recommends that everyone six months and older receive a flu vaccine each year. This recommendation has been in place since February 24, 2010 when CDC’s Advisory Committee on Immunization Practices (ACIP) voted for “universal” flu vaccination in the U.S. to expand protection against the flu to more people. While everyone should get a flu vaccine each flu season, it’s critically important that certain people receive a flu vaccine either because they are at high risk of having serious flu-related complications or because they live with or care for people at high risk for developing flu-related complications.