President Bush met for about 40 minutes yesterday with the chief executives of major vaccine and pharmaceutical manufacturers, emphasizing to them the importance he places on ramping up medical protections against pandemic flu and discussing strategies for increasing the global capacity for vaccine production, White House and other officials said.

The conversation was the latest in a series of meetings between drug company executives and federal health officials, Health and Human Services Secretary Mike Leavitt told reporters yesterday at the White House and at a follow-up briefing at HHS headquarters.

"There's no secret about the fact that our vaccine manufacturing capacity domestically is not what we need it to be," Leavitt said. "We've got to improve in that area."

The executives, from Chiron, GlaxoSmithKline, Merck, Sanofi-Aventis, Wyeth and Gaithersburg-based MedImmune, said little as they left the White House. But David Williams, chief executive of Sanofi Pasteur, which makes vaccines for Sanofi-Aventis, said: "We're very encouraged. We think a national plan is going to come into place."

Anthony S. Fauci, who as chief of infectious diseases at the National Institutes of Health has been involved in several flu-related briefings with the president and others in recent weeks, including yesterday's, said that although the current impetus comes from the avian flu pandemic that scientists fear is now brewing in Southeast Asia, the key to being able to produce a pandemic vaccine on short notice is to have a robust vaccine production infrastructure in place.

"The issue is: How do we build a sustainable capacity so we're not always in crisis mode," Fauci said.

To accomplish that, he said, liability issues must be addressed. Currently, federal vaccine liability protections apply only to routine childhood vaccines.

Also key will be issues of profitability, since the domestic market for ordinary flu vaccines is currently too small to attract companies beholden to shareholders.

One way to get over the profit hurdle, Fauci said, is to create policies and a "national ethic" in which greater numbers of people take advantage of the benefits of getting vaccinated against flu annually. In the short term, that would protect more people each winter, he said, and in the longer term it would keep the industry healthy and primed for an emergency.

The chief executives who met with Bush were precluded by antitrust laws from discussing in one room the details of their evolving strategies, but each company will hone its approaches in one-on-one meetings with federal officials, Leavitt said.

Leavitt, who leaves today on a 10-day trip to Asia to build political bridges and scientific collaborations with health officials in the region, emphasized that vaccines are just one part of a larger pandemic strategy that includes antiviral drugs, animal health surveillance and public health measures.

Although he said that the multi-pronged process is going well and promised that a national pandemic preparedness plan is on the brink of being released, several Democratic senators said yesterday the administration response to the threat of avian flu has been sluggish.

In a letter to Leavitt, Senate Minority Leader Harry M. Reid and five other Democrats emphasized that the government has stockpiled relatively small amounts of the antiviral drug Tamiflu.

The United States has 4.3 million 10-dose courses of treatment stockpiled -- enough for less than 2 percent of the population -- and has ordered 8 million additional courses.

By contrast, several European nations have already placed huge orders to cover 20 to 40 percent of their populations, leading some to doubt that any significant U.S. order could be filled in less than a year or two.

"The World Health Organization has recommended that countries stockpile enough antivirals to treat at least 25 percent of their populations," the senators wrote. "Explain why our preparations are behind those of other nations."

Leavitt, however, said, "I have had discussions with Roche," Tamiflu's Swiss-based maker. "I have every reason to believe," he added without elaborating, "that our needs for Tamiflu will be meetable."

Anthony S. Fauci of the NIH, foreground, and Mike Leavitt, secretary of health and human services, talk about flu vaccines.