Throughout most of human history, infectious diseases killed half of all children. Today, thanks to public-health projects such as vaccination programs, almost all children in the United States will reach adulthood. Vaccination programs are central to modern public health, yet our country relies on foreign suppliers and old technology to provide our flu vaccine. The United States urgently needs to modernize and improve its vaccination system.

Our flu-vaccine program has not shared the great success of many vaccination programs in controlling deadly scourges such as polio, smallpox, diphtheria and tetanus. The seasonal influenza/pneumonia syndrome claims about 36,000 lives and $10 billion in lost productivity each year. Medical costs also exceed $10 billion a year. The solution is to vaccinate more people, especially children, who primarily circulate the flu. This will require more vaccine, and our current vaccine-production system is inadequate to meet the need.

There are not enough vaccine producers worldwide, so we are vulnerable to shortages, as happened dramatically last fall and winter, when half the country's supply was discarded because of contamination at a major production facility in England.

Suppose that pandemic avian flu emerges and global demand for vaccine outpaces production. Will foreign suppliers provide the United States with adequate vaccine? It is incredible that we do not maintain adequate domestic capacity for this vital commodity.

Flu-vaccine technology has been stagnant for 50 years. Flu-vaccine viruses are grown in chickens' eggs - millions of them. The process is cumbersome and slow. Recombinant DNA and cell-culture methods can produce vaccines with distinct advantages in the numbers of doses that can be produced very quickly. Cell-culture methods have produced other vaccines for decades, and recombinant DNA techniques for other diseases are in development. The United States needs to support the development of flu vaccines using these new methods.

The possibility of an avian-flu pandemic increases our urgency. In 1918, an especially virulent pandemic flu virus killed 40 million people. Recent research shows that the 1918 strain is very similar to the avian flu strain now circulating in Southeast Asia. If the current strain mutates so that it, like the 1918 strain, readily transmits among people, then millions of Americans could die.

Recently, the Bush administration put forth a preparedness plan to combat pandemic avian flu. Foremost, we will work with other nations to squelch outbreaks before they become pandemic. In addition, we will stockpile anti-flu medications and vaccines. Third, we will develop domestic plans to combat avian flu if it reaches our shores. All of these approaches are appropriate, and if successful, will save lives. Let's examine the vaccination portion of the plan.

Currently, drug companies are producing an avian-flu vaccine using old technology, but it will take three to five years to produce enough to fully protect the United States. Ideally, the Bush plan will use recombinant DNA and cell-culture techniques to increase the rate and scale of vaccine production. Additionally, President Bush seeks liability protection for vaccine producers. These are important steps, but more are needed. Market economics do not favor domestic flu-vaccine production.

The federal government is the largest flu-vaccine consumer, but it purchases at rates that offer minimal profits to drug companies. Because standard flu-vaccine production does not require a highly trained work force, the vaccine industry has moved offshore to reduce production costs.

To rebuild a domestic industry, we should offer economic incentives, such as tax breaks, for domestic production. We should also provide market guarantees at reasonable prices for seasonal as well as pandemic flu vaccines. And we should streamline the regulatory process at new domestic facilities. The costs of these reforms would be far outweighed by the economic benefits of a healthier population.

The -same infrastructure would help us control both the seasonal and pandemic flu. A modernized domestic-vaccine production capacity will also make it easier to respond to bioterror attacks or to emerging diseases. We must fix our vaccination system now - too many lives are at stake.

• James Curran is a professor of biology at Wake Forest University.