November 1, 2004

On October 5, 2004, the United States learned that only half the anticipated doses of influenza vaccine would be available in preparation for the upcoming flu season because Chiron Vaccines, one of only two manufacturers of inactivated influenza vaccine, had its license to manufacture Fluvirin suspended. This may be the most abrupt and untimely interruption of the vaccine supply we have experienced but, as health-care providers for children well know, it isn't the first.

Since 2000, five vaccine products have been in short supply at one time or another. These include vaccines that protect against eight of the 11 diseases for which healthy children are routinely immunized. Shortages have lasted as long as 18 months and have necessitated regular deferral of certain vaccinations.

As is the case for Chiron's Fluvirin, supply interruptions were sometimes abrupt and unanticipated. But the consequences of these previous interruptions were not easily tabulated; most of the infections against which routine immunizations protect do not circulate regularly because of the effectiveness of the vaccine program for children, and an interruption of six to 18 months is not likely to cause large numbers of hospitalizations or deaths.

The CDC, the American Academy of Pediatrics, and others have worked quickly to distribute priority lists for vaccination candidates. Most health-care providers will work hard to adhere to that list, but extremely difficult choices will nevertheless have to be made. Is a 10-year-old with asthma, for example, more-or less-deserving of vaccine than an 8-year-old healthy child who has a 3-month-old sister? Many providers will receive less vaccine than was ordered, and rationing will be necessary.

How did this happen? In recent years, various agencies and organizations have investigated the shaky nature of the vaccine supply, and the National Vaccine Advisory Committee, the United States General Accounting Office, the Institute of Medicine, and other groups have made recommendations for ensuring adequate supplies. In 1983, seven manufacturers produced the four vaccine products regularly recommended at that time for healthy children. By 2003, five manufacturers were producing all eight recommended products that protect against 11 diseases, and five of those products-inactivated polio, measles-mumps-rubella, pneumococcal conjugate, tetanus and diphtheria toxoids (Td), and varicella-are produced by just one manufacturer.

Manufacturers are leaving the vaccine business for various reasons, and those reasons have been described in reports issued by the bodies just mentioned. But, as the October shutdown of the Chiron influenza vaccine plant in Liverpool, England, illustrates, problems and pitfalls in production are many, and they may be unpredictable. What is predictable is this: There will be more interruptions in supply unless the federal government takes steps to ensure the stability of pharmaceutical companies that manufacture vaccines.

A great deal of talk has been made during this past election season about keeping this nation safe. We have not devised a foolproof method for preventing hospitalization and death from influenza, and now even our ability to reduce the impact of this disease has been reduced by 50%. What is "homeland security," if not protection against a viral terrorist that kills thousands every year?

Julia A. McMillan, MD, Editor-In-Chief of Contemporary Pediatrics, is professor of pediatrics, vice chair for pediatric education, and director of the pediatric residency training program, Johns Hopkins University School of Medicine, Baltimore.