Washington Editor

WASHINGTON - The World Health Organization (WHO) Wednesday declared that an influenza pandemic was imminent, raising the alert level to Phase 5 - the level just before declaring a full-blown pandemic.

But U.S. health officials said they already have been taking measures to address a possible pandemic, including developing a vaccine to fight the H1N1 swine flu virus.

"The influenza pandemic must be taken seriously precisely because of the capacity to spread rapidly to every country in the world," said WHO Director-General Margaret Chan.

On the positive side, she said, "the world is better prepared for an influenza pandemic than at any time in history."

For the first time, Chan said, "we can track the evolution of a pandemic in real-time."

From the first outbreak barely a month ago in Mexico to the first confirmed U.S. case last week in San Diego, the 2009 H1N1 influenza virus has moved very quickly, now killing the first person inside U.S. borders, Sen. Joe Lieberman (D-Conn.) noted during a Senate hearing Wednesday.

While Homeland Security Secretary Janet Napolitano was on Capitol Hill Wednesday describing measures the administration is taking to keep the virus contained, federal health officials, led by newly sworn-in Health and Human Services (HHS) Secretary Kathleen Sebelius, were confirming at a press conference a few blocks away that the U.S. cases of the swine flu virus had risen to 91, now infecting Americans in 10 states.

WHO reported that 148 cases had been reported from nine countries: Austria (1), Canada (13), Germany (3), Israel (2), Mexico (26), New Zealand (3), Spain (4), the UK (5) and the U.S. (91).

Earlier Wednesday, Keiji Fukuda, WHO's assistant director-general of health security and environment, hinted during a morning press briefing that world health officials were moving closer to raising the pandemic alert level from Phase 4, which is characterized as sustained human-to-human transmission, to Phase 5, where the sustained transmission had been shown in two or more countries. Phase 6 - widespread sustained transmission - is the highest alert.

Fukuda said that WHO wanted to be "absolutely sure" before making that "significant milestone" decision to raise the alert to Phase 5.

But hours later Wednesday, in the second briefing of the day, Chan officially declared the alert level had been raised and said that all countries should now immediately activate their pandemic preparedness plans.

"Countries should remain on high alert for unusual outbreak of influenza-like illness and severe pneumonia," Chan said, noting that nations should be engaged in heightened surveillance, early detection activities, treatment of cases and infection control in all health facilities.

"This change to a higher phase of alert is a signal to governments, to ministries of health and other ministries, the pharmaceutical industry and the business community that certain actions now should be undertaken with increased urgency and at an accelerated pace," she said.

The greatest current uncertainty, Chan said, is the level of severity the swine flu will reach.

"We need to continue to monitor its evolution and get more specific data and information to answer more precisely this question," she said.

At Wednesday's HHS press briefing, Richard Besser, acting director of the Centers for Disease Control and Prevention (CDC), confirmed the first U.S. death from the H1N1 swine flu virus in a 22-month-old boy from Mexico City who died earlier this week in a Houston-area hospital.

The young boy, who Texas health officials said had several underlying health problems, had traveled with his family on April 4 on a commercial flight from Mexico City to Brownsville, Texas, to visit relatives there.

The child developed a fever on April 8 followed by other influenza-like symptoms and within days was admitted to a Brownsville hospital, according to the Texas Department of State Health Services. The boy was later transferred to a Houston-area hospital where he died, officials said in a statement.

"While we still don't know what this virus will do, we expect to see more cases, more hospitalizations, and unfortunately, we are likely to see additional deaths from the outbreak," said Sebelius, who was confirmed Tuesday night by the Senate in a 65-to-31 vote.

Sebelius, who noted that she met with White House officials Tuesday night "immediately" after being sworn in to discuss the administration's response to the swine flu, said HHS has been working closely with state and local health departments and others to ensure that any American infected with the H1N1 virus receive antivirals from the Strategic National Stockpile - a national repository of drugs and medical supplies deployed for disasters.

The CDC and the FDA have begun the process to develop a vaccine against the new H1N1 influenza virus, she said.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, noted that the CDC has isolated the strain that will be used for the vaccine. "The virus reference strain has been distributed to appropriate people and will continue to be distributed to those who utilize it," he told reporters Wednesday.

The National Institutes of Health, which will be responsible for conducting the clinical trials on the pilot lots that will emerge from the agency's pharmaceutical partners, is "already geared up," Fauci said.

The trials, which will determine the safety, immunogenicity and the proper dose of the vaccine, "will take a period of months that will probably begin within a couple of months," he said.

"We have begun the process, we are in full gear and the process is more speedy than it has ever been before," Sebelius said. "We are committed to ensuring that these vaccines are safe," she added, noting that the HHS and the FDA will monitor the manufacturing of a potential vaccine and conduct strict oversight.

"We will be working quickly, but safety is and will remain our top priority," Sebelius said.

In other swine flu news:

• CombiMatrix Corp., of Mukilteo, Wash., said it has updated its Influenza-Detection Microarray to include sequence information for the H1N1 swine flu virus. The firm said that the previous version of the Influenza-Detection Microarray already detected many strains of swine flu in addition to the pathogenic avian flu.

• DxNA, of St. George, Utah, said it was developing a diagnostic test for its GeneSTAT pathogen detection platform to detect the H1N1 swine flu virus anywhere it is needed in about 45 minutes using a portable device that weighs less than 10 pounds. The company said it anticipated having a product ready for evaluation in one to two weeks. The firm said it was approaching the FDA about granting an emergency use authorization under the Project BioShield Act of 2004 for the H1N1 strain of swine flu test using the GeneSTAT platform. DxNA initially developed its rapid, portable molecular test to detect H5N1 avian influenza for markets around the world. DxNA said that test is now being validated by the Chinese government and other global health organizations.

• Qaigen NV, of Venlo, the Netherlands, said two of its tests can be used to screen for the swine flu. The firm said that data analysis of the viral gene sequences showed that its artus Influenza LC RT PCR Kit and the Resplex II 2.0 Kit can be used to detect whether or not influenza A virus sequences are present in a sample, including the H1N1 subtype.