THE INFLUENZA A virus known as H5N1 is found mostly in birds. Yet humans can get it, too. Since 2003, there have been more than 600 confirmed cases, in which about 60 percent of the victims have died. So far, the strain has not spread between humans. But last year, a pair of laboratory experiments, financed by the National Institutes of Health, showed that with genetic tweaks, the avian flu could be transmitted person to person, raising the specter of a deadly pandemic if it ever got into the wild. One of the scientists, Ron Fouchier of the Erasmus Medical Center in Rotterdam, said his team had created “one of the most dangerous viruses you can make.”

When Mr. Fouchier wanted to publish his work, an uproar ensued. Critics said the details would enable terrorists to create a virus capable of killing millions of people. Scientists responded that censoring the research could hinder flu research necessary to predict or prevent a pandemic, and to treat its victims. After a debate over scientific freedom and public security, and new data from Mr. Fouchier, a federal advisory committee voted to permit publication of the papers in full, although some board members wanted to withhold part of the work.

This week, the journal Science published the paper, showing that it would take as few as five mutations to turn H5N1 into an airborne transmissible disease in mammals. The other paper, by Yoshihiro Kawaoka of the University of Wisconsin and University of Tokyo, was published by Nature in May.

But this is not the end of the story. Rather, it marks the beginning of an important chapter for both science and security.

Today’s advances in the life sciences are revolutionary. Whole genomes can be mapped in a matter of hours. But biological research is dual-use: That which creates medicines to save lives can also be deployed to create disease.

The avian flu experiments got all the way to completion before they were questioned. This was a mistake. The United States and other nations need a more sophisticated process for vetting research for possible security threats without discouraging or impairing scientists. This is more difficult than it sounds. Freedom of inquiry in science is not only a cherished principle that must be protected, but it also generates colossal benefits for society. An entirely new oversight process is needed that will be responsive to both science and security, clearing experiments in advance and making sure lab safety precautions are met. The new system must allow research like the avian flu studies to proceed but create a secure channel for researchers to share sensitive details.

In March, the federal government took a preliminary step by publishing guidance for handling “dual use research of concern,” covering experiments intended for beneficial purposes but with a risk of misuse. Much more needs to be done. The burden of biosecurity should not be borne by government alone. Scientists must show leadership and recognize that freedom to discover carries a responsibility to remain vigilant for those who would misuse the basic building blocks of life.