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CDC Lifts Restrictions to Expand Seasonal Flu Vaccination

By Eric Toner, M.D., November 14, 2005

Everyone Eligible for Vaccination

Last year, following a widely reported shortage of flu vaccine, millions of doses were left unused as a result of confusion about priorities and eligibility. To prevent the same from happening again and to maximize use of seasonal flu vaccine, on October 24, 2005, the CDC lifted prior restrictions and now says that everyone is eligible to receive inactivated flu vaccine.

In the past, vaccine was restricted to priority groups to ensure that those at highest risk had first access to limited supplies. Because the demand for flu vaccine falls off quickly after November, the CDC decided to make the vaccine available to all in October to promote use rather than waste of vaccine supplies.

The live, attenuated, intranasal flu vaccine (FluMist®) has not been subject to prioritization and is licensed for healthy, non-pregnant people between 5 and 49 years of age. While equally as safe and effective as the inactivated vaccine, only 1.6% of vaccinated adults receive FluMist® [1].

Vaccination of Healthcare Workers Remains a High Priority

While annual vaccination is recommended for healthcare workers, the CDC reports that only 40% were vaccinated in 2003 [2]. Because vaccination of healthcare workers has been associated with both reduced absenteeism and fewer patient deaths, vaccination of this group remains a high priority.

Compelling Reasons for Broad Vaccination

Among adults in all priority groups, 34.8% reported receiving a flu vaccine last year, compared with just 4.4% of adults aged 18-64 years who were not in a priority group [1]. Historically, the CDC has recommended vaccination only for those at high risk of complications from the flu and for caretakers of those at risk. There are, however, two compelling reasons to shift to a policy promoting broad vaccination:

  1. Increased use of seasonal flu vaccine will stimulate increased vaccine manufacturing capacity, which will help with preparation for a pandemic. A pandemic flu vaccine will be manufactured in the same facilities that produce seasonal flu vaccines. The rate of production depends on the manufacturing capacity of those existing facilities, which is determined by usual annual demand. Thus, a sustained increase in annual demand, over several years, will lead to increased pandemic production capacity. Broad vaccination will create that type of demand [3].

  2. A reduction in the overall incidence of influenza in the community is likely to reduce the risk of infection in high risk groups. Although the elderly have been the main focus of the influenza vaccination strategy, children, not the elderly, are the greatest spreaders of flu. If enough healthy spreaders can be immunized, herd immunity can be achieved, which will reduce the incidence of flu among those at high risk. Several studies have shown that vaccinating school-aged children is a more effective strategy to reduce flu deaths among the elderly than vaccinating the elderly themselves [4].

Nearly all influenza experts agree that a change in our approach to annual influenza vaccination is essential. The CDC’s important first step in that direction is encouraging.


  1. Centers for Disease Control and Prevention (CDC). Estimated influenza vaccination coverage among adults and children--United States, September 1-November 30, 2004. MMWR Morb Mortal Wkly Rep 2004;53(49):1147-53.

  2. Harper SA, Fukuda K, Uyeki TM, et al. Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2005; 54(RR-8):1-40.

  3. Stohr K, Esveld M. Will vaccines be available for the next influenza pandemic? Science 2004;306(5705):2195-6.

  4. Cohen J. Immunizing kids against flu may prevent deaths among the elderly. Science 2004;306(5699):112