An unusually large demand for the influenza vaccine this season has led to shortages in some vaccine supplies.

By John D. Zoidis, MD; and Phyllis C. Braun, PhD

The current influenza season is one of the worst in recent years. As of mid January, the number of states reporting widespread influenza activity has finally begun to decrease, but the mortality rate for pneumonia with influenza (10.2%) continues to exceed the epidemic threshold (8.1%).1 For the week ending January 17, five state health departments and New York City reported widespread influenza activity, 31 states reported regional activity, and eight states reported local activity.1

The trivalent influenza vaccine prepared for the 2003-2004 season includes inactivated strains of A/New Caledonia/20/99 (H1N1); A/Panama/2007/99 (H3N2); and B/Hong Kong/330/2001-like virus.2 The intranasal vaccine contains live but weakened strains of influenza virus, and is approved for use in healthy people aged 5 to 49 years.

An unusually large demand for the influenza vaccine this season has led to shortages in some vaccine supplies. The inactivated vaccine, which is given by intramuscular injection, is most affected by the shortage. Two other factors contributed to the shortage. First, the composition of the vaccine changes each year and is based on the strains of influenza expected to circulate during the upcoming influenza season. This year, the type of strain needed for the vaccine was difficult to grow and did not grow as quickly as expected. Second, the US Food and Drug Administration found manufacturing problems at the plants of two vaccine suppliers.

The US Centers for Disease Control and Prevention (CDC) established state-specific contingency plans to deal with shortages of influenza vaccine.3 In general, the CDC recommends that available vaccine be given on a health-priority basis.3 Individuals who are at highest risk for influenza complications are assigned the highest priority. These people include nursing-home patients, adults and children of any age with any chronic heart or lung disease (including asthma), and children and teenagers on long-term aspirin therapy.3 The next priority category includes those 65 and older, health care workers, and women in the second or third trimester of pregnancy.3

With supplies of the inactivated vaccine in short supply and supplies of the intranasal vaccine decreasing, preventive measures are especially important this year. Clinicians should encourage their patients to follow the preventive guidelines issued by the AAP:4

  • wash your hands or use alcohol hand solutions after being in public or around anyone with a cold or influenza;
  • when coughing or sneezing, turn your head and cough or sneeze into a disposable tissue (and dispose of it promptly); if no tissue is available, cough or sneeze into the inside of the elbow;
  • do not take young children or those with immune-system problems into large crowds unnecessarily when influenza is known to be present in the community;
  • avoid close contact (such as holding or kissing) between infants and anyone who has a cold or influenza;
  • stay home from work or school if you are currently suffering from influenza (with fever, muscle aches, and cough);
  • do not share items that go into the mouth (such as drinking cups or straws);
  • clean commonly touched surfaces such as door knobs, refrigerator handles, telephones, and water faucets frequently if someone in the house has a cold or influenza; and
  • do not smoke around children.

In addition to recommending preventive measures to patients, practitioners should be looking for patients who may fall into a high-priority influenza vaccination category.


John D. Zoidis, MD, is a contributing writer for RT.
Phyllis C. Braun, PhD, is professor, Department of Biology, Fairfield University, Fairfield, Conn.
For more information, contact [email protected].


1. Centers for Disease Control and Prevention. Weekly report: influenza summary update. Week ending January 10, 2004. Available at: weekly/. Accessed January 20, 2004.
2. US Food and Drug Administration. Influenza virus vaccine 2003-2004. Available at: http://www. Accessed January 20, 2004.
3. Centers for Disease Control and Prevention. State flu vaccine supply contingency plans. Available at: http://www.cdc. gov/nip/flu/state-contingencies. htm. Accessed January 20, 2004.
4. American Academy of Pediatrics. Information for families about flu vaccine shortage. Available at: new/decimmunization.htm. Accessed January 20, 2004.