WHO Officials Focus on Vaccine as H1N1 Spreads

"For the first time in humanity, we are seeing, or we may be seeing, pandemic influenza evolving in front of our eyes," WHO Director-General Dr. Margaret Chan told a meeting of her U.N. agency's World Health Assembly in Geneva.

But Chan says she is not raising the world swine flu alert level just yet. The epidemic is in "a grace period" with the WHO alert remaining at phase 5 out of a possible six for the last month. She told the WHO's annual assembly that no one can say how long this period will last.

Chan says the danger now is that the swine flu virus could mix with other flu strains and become more dangerous.

"Unlike the avian virus, the new H1N1 virus spreads easily from person to person, spreads rapidly within a country once it becomes established, and is spreading rapidly to new countries. We expect this pattern to continue," she said.

Chan said H1N1 may pose a particular risk when it mixes with the H5N1 avian flu virus, which is now "entrenched" in poultry in several countries.

"No one can say how this avian virus will behave when pressured by large numbers of people infected with the new H1N1 virus," she said.

Britain, Japan, China and other nations urged WHO to change the way it decides to declare a pandemic, saying the agency must consider how deadly the virus is, not just how fast it is spreading.

The debate arose as WHO began its annual meeting, a five-day event attended by hundreds of health experts from the agency's 193 member nations. The focus of the summit will be to discuss how to fight the virus with vaccines and drugs, as well as what would trigger the WHO to declare a full pandemic.

Also Monday, the Centers for Disease Control and Prevention reported that the new strain is circulating in 48 U.S. states and has showed no signs of abating, with five deaths and more than 5,000 confirmed cases. Around the globe, the virus has been confirmed in 8,829 people in 40 countries, killing 74 -- mostly in Mexico.

Experts have said more than 100,000 people are likely infected with the virus, which appears mild but is still worrisome since most patients are young adults, teens and children.

Last month, WHO raised its global pandemic alert level to 5 on a 6-point scale in response to the spread of H1N1 in North America, which has had 95 percent of the nearly 9,000 confirmed infections to date.

WHO has said it is watching the situation in Japan closely, but it was not clear yet whether the outbreak, the largest outside the Americas, would trigger a move to level 6.

Under WHO rules, signs that the disease is spreading in a sustained way in a second region of the world would prompt a declaration that a full pandemic is under way. Other large clusters have been seen in Spain and Britain.

A WHO designation of phase 6 flu would put countries on even higher alert about the flu strain and give more impetus to pharmaceutical efforts to fight it.

Chan and U.N. Secretary-General Ban Ki-moon will meet top pharmaceutical executives on Tuesday to discuss their ability to make vaccines to fight the strain. Delegates will seek an agreement on how samples of the virus should be handled and shared with pharmaceutical companies.