(AP) -- As swine flu cases hit 6,500 worldwide, World Health Organization officials were meeting with vaccine manufacturers and other experts in Geneva on Thursday to discuss making a vaccine to fight the virus.
The meeting focused on the major questions surrounding a possible swine flu vaccine, such as how much should be produced, how it will be distributed and who should get it.
The expert group's recommendations will be passed to WHO Director-General Margaret Chan, who will issue advice to vaccine manufacturers and the World Health Assembly next week.
But some experts feel the main decision has already been made.
"It's a foregone conclusion," said David Fedson, a vaccines expert and former professor of medicine at the University of Virginia. "If we don't invest in an H1N1 (swine flu) vaccine, then possibly we could have a reappearance of this virus in a mild, moderate, or catastrophic form and we would have absolutely nothing."
Flu vaccine companies can only make one vaccine at a time: seasonal flu vaccine or pandemic vaccine. Production takes months and it is impossible to switch halfway through if health officials make a mistake.
Vaccine makers can make limited amounts of both seasonal flu vaccine and pandemic vaccine - though not at the same time - but they cannot make massive quantities of both because that exceeds manufacturing capacity.
Seasonal flu kills up to 500,000 people a year. At the moment, health officials aren't sure how deadly swine flu is, and whether they will need more seasonal flu vaccine or swine flu vaccine. And if the swine flu mutates, scientists aren't sure how effective a vaccine made now from the current strain will remain.
WHO estimates that 1 to 2 billion doses of swine flu vaccine could be produced every year, though the first batches wouldn't be available for 4 to 6 months.
The U.S. Centers for Disease Control and Prevention is currently working on a "seed stock" to make the vaccine, which should be ready in the next couple of weeks. That will be distributed to manufacturers worldwide so they can start producing the vaccine.
WHO is also negotiating with vaccine producers to save some of their swine flu vaccine for poorer nations. Many rich nations like Britain, Canada, Denmark, France, Switzerland and the United States signed deals with vaccine makers years ago to guarantee them pandemic vaccines as soon as they're available.
As of Thursday, at least 33 countries reported nearly 6,500 cases of swine flu worldwide, with 65 deaths. According to WHO's pandemic alert level, the world is at phase 5 - out of a possible 6 - meaning that a global outbreak is "imminent."
"It's a no-brainer," Fedson said of the decision to make swine flu vaccine. "All that's being discussed now is the details of how to make sure you have enough seasonal flu vaccine and the logistics of making the switch to H1N1 vaccine production."
North America has been the hardest-hit continent. The United States has reported 3,352 laboratory-confirmed cases of swine flu, including three deaths. Mexico has 2,446 cases and 60 deaths, while Canada has 389 cases with one death, according to WHO figures.
Spain and Britain have the most cases in Europe, at 100 and 71 respectively.
In Central America, Costa Rica has eight cases and one death and Panama has 29 cases.
©2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Explore further: Non-smokers exposed to three times above safe levels of particles when living with smokers