Drug manufacturers won't be able to start making a vaccine for H1N1 flu until mid-July at the earliest, weeks later than previous predictions, the World Health Organization said Tuesday.
It will then take months to produce a new vaccine.
The disclosure that making a swine flu vaccine is proving more difficult than experts first thought came as U.N. Secretary-General Ban Ki-moon and WHO chief Dr. Margaret Chan met Tuesday with representatives from about 30 pharmaceutical companies to discuss the subject.
After the meeting, Ban declared that solidarity was the key to resolving the flu outbreak, urging governments to make sure all countries have access to drugs and vaccines.
He also said virus samples and flu data must be shared and "self-defeating" measures like trade and travel bans should be avoided.
"We do not yet know how far and how fast it will spread, how serious the illness will be and, indeed, how many lives will be lost," Ban told WHO's annual assembly in Geneva. "Global solidarity must be at the heart of the world's response."
"(It) must mean that all have access to drugs and vaccines," he said.
Health officials from around the world are meeting here this week to discuss the outbreak that has infected 9,830 people in over 40 countries, killing at least 79 of them.
According to vaccine experts convened by WHO, the H1N1 flu virus is not growing very fast in laboratories, making it difficult for scientists to get the key ingredient they need for a vaccine, the "seed stock" from the virus, the agency reported.
Previously, WHO officials had estimated that production could start in late May, and would take four to six months.
Experts also found no evidence that regular flu vaccines offer any protection against H1N1 flu, it said.
Vaccine experts estimated under the best conditions, they could produce nearly 5 billion doses of vaccine over a year after beginning full-scale production.
Mass producing a pandemic vaccine would be a gamble, as it would take away manufacturing capacity for the seasonal flu vaccine that kills up to 500,000 people each year. Some experts have wondered whether the world really needs a vaccine for an illness that so far appears mild.
Chan said it would be impossible to produce enough vaccine for all 6.8 billion people on the planet -- a situation that could set off a global scramble where rich countries outbid poorer nations for the vaccine.
She said some vaccine makers have offered to provide some H1N1 flu vaccines if a worldwide outbreak is declared, but no agreements have yet been signed. Only two companies made the tentative offers.
WHO said one company with limited production capacity has offered to share half of its vaccine doses. Another large multinational pledged to provide 50 million vaccine doses at a cheaper price for U.N. agencies to buy for poor countries.
WHO asked all flu vaccine makers to donate at least 10 percent of their production or offer reduced prices for poor countries, but is waiting for most responses.
The impact of a pandemic -- a global epidemic -- is expected to be worse in poor countries, where people with other diseases like AIDS and malaria are more susceptible to H1N1 flu and national health systems are less able to respond.
U.S. Health and Human Services Secretary Kathleen Sebelius said Tuesday the U.S. felt it had a responsibility to ensure that both antiviral drugs and any new vaccine are also available to poor countries.
The United States has so far refrained from reserving any new vaccine, unlike Britain, Canada, Denmark, France, Switzerland and other countries.
Sebelius said the United States is working to boost its production capacity for seasonal flu vaccines so --in the event of a global outbreak -- those factories can switch to the pandemic flu strain.
"At this point we have not placed orders for vaccine," Sebelius told reporters in Geneva. "There is still so much uncertainty about this virus that it is really premature for us to even make a determination of how many people would appropriately be vaccinated, in what order, how many doses would be required."
These are the issues Ban and Chan discussed with vaccine makers, including top producers Novartis, Sanofi-Aventis, GlaxoSmithKline and Baxter International as well as drugmakers from developing countries.
One expert, however, thought the 5 billion doses estimate was too optimistic.
"We should go forward with production as quickly as possible, but we should be cautious" about predictions, said David Fedson, a vaccine expert and former medical professor at the University of Virginia.
He also wondered about the political issues involving vaccine distribution, saying countries with vaccine plants might not be willing to ship pandemic vaccines elsewhere before all of their own citizens were vaccinated.
On Monday, dozens of governments lobbied WHO to tread carefully before next raising its flu alert to the highest pandemic level of phase 6. The level currently stands at phase 5 -- saying a global outbreak is "imminent."
Britain, Japan, China and others said declaring a global outbreak could cause unnecessary panic and confusion, especially since the virus has turned out to be less deadly than feared.
The vaccine experts emphasized that WHO's declaration of a pandemic should not automatically force vaccine makers to switch from making regular flu vaccine to pandemic vaccine.
In addition, they said even if H1N1 flu vaccine production began, that did not mean that countries should start immunizing large groups of people.
The experts told WHO that it should come up with targeted advice on which groups of people need the vaccine first. They also planned to meet again in several weeks to decide whether large-scale production of the vaccine should begin.
Since the outbreak began last month, 79 people have died from the disease -- 72 in Mexico, five in the U.S., one in Canada and one in Costa Rica, WHO says. Another U.S. death -- that of a 16-month-old -- is being investigated for swine flu.
Japan confirmed dozens more H1N1 flu cases Tuesday, bringing its tally to 176, but none of the patients were in serious condition. Its 41 new cases mostly involved teenagers with no clear links to foreign travel.
Japan is the hardest-hit nation outside of North America in the flu outbreak. The United States has the most confirmed H1N1 flu cases, followed by Mexico and Canada.
(Copyright 2009 by The Associated Press. All Rights Reserved.)