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CDC Expands Influenza Vaccination Window, Acknowledges Supply Problems

Kate Traynor

People at high risk for influenza-related complications should receive their flu shot any time in October or November this year, says the Centers for Disease Control and Prevention (CDC). This expands by about two weeks last year’s recommended optimal vaccination period, which ran from October through mid-November.

CDC’s recommendations about the timing of vaccinations for the upcoming influenza season appear in the newly updated "Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP)" (PDF). ACIP also advised

  • Early vaccination, in October or November, of health care workers who might transmit the virus to patients at high risk for developing influenza-related complications,
  • Vaccinating throughout the influenza season any vulnerable American who misses the October–November window,
  • Making a special effort throughout December to vaccinate adults 50–64 years of age, and
  • Delaying until at least mid-October large-scale programs to vaccinate the general population.

ACIP stressed that vulnerable Americans can be vaccinated as early as September during a hospitalization or routine office visit. But the committee acknowledged that the timing of vaccination depends on availability of the vaccine, which was in short supply during the recommended peak vaccination period last fall. Shortages of or disruptions in influenza vaccine supply are a possibility this season, ACIP said.

A General Accounting Office (GAO) report discussing last year’s influenza vaccine shortage was scheduled for release on May 15. According to the San Francisco Chronicle, which obtained an advance copy of the report, GAO recommended developing "voluntary guidelines for vaccine distribution" to get the vaccine to patients most in need of it each year. GAO, said the Chronicle, concluded that the government can do little to avoid future shortages of influenza vaccine, since nearly all of the product is made and distributed by private companies and medical groups.

This year’s vaccine, like the one used last season, will contain material derived from an influenza strain that has never been used in the trivalent mix, a factor that could contribute to vaccine shortages.