WASHINGTON - The Johns Hopkins doctor who decades ago led the worldwide effort to wipe out smallpox is wasting no time trying to inoculate the nation against a bioterrorist attack.

Recently asked by U.S. Health and Human Services Secretary Tommy G. Thompson to chair an advisory commission on bioterrorism, Dr. Donald A. Henderson didn't pause to set up an office or even a desk as he began meetings at HHS here this week with top health officials.

Henderson, 73, has felt a sense of urgency about preparing for the unthinkable - an urgency only now shared by much of the nation - since the mid-1990s, pressing his case before Congress, the CIA and World Health Organization.

While Henderson, former dean of faculty of the Hopkins School of Public Health, has said that a biological weapons release is not a likely event, he says the risk is not zero. And he was concerned enough about the possibility to establish the Hopkins center for biodefense studies two years ago.

"He's been the pioneer in the civilian world for trying to combat bioterrorism," said James Campbell, an infectious disease specialist at the University of Maryland.

As he hurries to come up with a coordinated medical and public health strategy for responding to a bioterrorist attack, he says the effort will not be easy or quick.

"We'll get better and better and better prepared," Henderson said in a phone interview yesterday. "But to really rebuild the public health system - which is a fundamental part of this - will require personnel, training and planning. It's going to take a number of years."

He said it would be several years before the public health system reached even a "reasonable" level of preparedness. It is now a network of 50 state and 3,000 local public health agencies, which Henderson said shouldn't even be called a "system," because it isn't coordinated in any meaningful way.

"It's not terribly able to respond," he said.

For instance, most hospitals are stressed by outbreaks of influenza and not able to handle even 25 to 50 acutely ill patients at a time. An outbreak of anthrax could require a hospital to tend to 500 people.

Hopkins, Henderson said, is one of the few hospitals in the nation with a plan for treating large numbers of patients.

What's more, many county and city health departments do not have 24-hour emergency phone numbers, and their officials are not equipped with pagers, cell phones or computers, he said.

In testimony before a Senate panel this week, Henderson, a science and technology adviser to President Bill Clinton and the first President Bush, said: "If we are to detect and rapidly identify a new health problem, public health officials must be available 24 hours a day, seven days a week, to take calls from clinicians reporting cases which may be suggestive of ... a bioweapons-related disease. This is not possible in most areas of the country."

The bioterrorism council, which will advise Thompson, will consist of public health officials from county to federal levels, hospital personnel, university doctors and researchers, even medical ethicists and lawyers.

Aside from overhauling the public health system, Henderson says, his council will also focus on development of vaccines and antibiotics.

Of the deadly agents that could be used by terrorists, Henderson says, anthrax is the most likely, but smallpox the most devastating.

Henderson spent 11 years leading the World Health Organization's campaign to eradicate smallpox. When the last case was tracked down in Somalia in 1977, it became the only infectious disease ever to be completely wiped out. Smallpox samples are still kept in some laboratories, and there is a fear that some could fall into the wrong hands.

Although Americans haven't been routinely vaccinated against the disease since 1972, there is enough smallpox vaccine left - up to 15 million doses - to handle a moderate-size outbreak, Henderson said. The Centers for Disease Control has stepped up its effort to deliver 40 million more doses, but production could take up to three years.

Most counties are not equipped for mass vaccinations, since they haven't engaged in such a process since delivering the oral polio vaccine in the early 1960s, Henderson said.

He has tried to calm some of the post-Sept. 11 hysteria, advising against buying gas masks, which he says are more likely to suffocate people than save them, and stockpiling antibiotics, which he says are only useful if you have the right one.

Still, he has urged Congress, as soon as possible, to send an additional $1.4 billion to $1.6 billion to the states for bioterrorism defense, on top of the $350 million the federal government is already spending this year on bioterrorism.

"It is difficult for me to exaggerate the deficiencies of our present public health capabilities," he said.