A global deal is tantalizingly close under which countries would share flu virus samples in exchange for access to affordable vaccines derived from them, thus saving lives in a pandemic, senior diplomats said.

Consensus has been reached across all regions, including Indonesia which three years ago stopped sharing influenza samples with the World Health Organization (WHO), but the United States has yet to give formal approval, they said Thursday.

The hope was to reach agreement by Friday on a political deal to be presented for approval by health ministers at the annual meeting of the U.N. agency scheduled for May 16-24.

"There is a package. Everybody is on board, including Indonesia. The U.S. delegation is checking with Washington overnight but the U.S. ambassador has recommended going along," one ambassador told Reuters late Thursday. An envoy from a major country in Asia called it a "model" agreement.

A U.S. spokesman in Geneva said: "Negotiations are still ongoing." He had no other details on the closed-door talks.

Negotiations began four years ago between WHO's 193 members after the deadly H5N1 bird flu virus emerged in southeast Asia. A year later, Indonesia stopped sharing flu virus samples with WHO's network of laboratories, demanding its share of vaccines.

Ambassadors Juan Jose Gomez Camacho of Mexico and Bente Angell-Hansen of Norway, who co-chair the talks, told reporters Tuesday that a deal was near but challenges remained, including how to define the drug industry's role and to overcome intellectual property issues.

They met top officials from 30 drug companies last week, including GlaxoSmithkline, Sanofi-Aventis and Novartis to win their support for providing affordable vaccines to developing countries lacking local vaccine makers.

The drug industry has now agreed to provide about one-half of an estimated $58 million needed a year to help poor countries through donations of vaccines and anti-virals as well as financing to improve their laboratory capacity, according to senior diplomats Thursday evening.

Industry executives have reported that current annual production capacity for pandemic flu vaccine is 1.1 billion doses, forecast to rise to 1.8 billion in four to five years. This was up from 500 million doses during the H1N1 swine flu pandemic of 2009-10, the first influenza pandemic in more than 40 years.

During the pandemic, the WHO coordinated the distribution of 78 million doses of vaccines to 77 countries from Cuba to Zimbabwe, but distribution was slow due to regulatory and other hurdles. The doses were donated by rich nations and drug makers.

The working group's draft document calls for having deals in place ahead of the next pandemic, including pre-purchase agreements with industry and governments to reserve a certain percentage of production capacity, for example 10 percent, earmarked for countries without access to vaccines.