Geneva - Swiss drugmaker Novartis said Thursday it was in the process of developing a vaccine with a booster that could inoculate against all known H5N1 antigenic variants, or all types of avian influenza.

A study mixing Aflunov, an investigative pre-pandemic avian influenza vaccine, with a Novartis adjuvant, "elicited a long-lasting immune response that could be rapidly boosted following a single dose of the vaccine."

The booster shot could be taken up to six years after the original vaccine was administered.

Novartis said in a statement that this could have public health benefits and might also aid the current battle with the outbreak of the H1N1 virus, known as swine influenza, particularly given the cross-reactive immune response, meaning the protection against more than the one strain in the vaccine.

"We will use these new insights," Andrin Oswald, CEO of Novartis Vaccines and Diagnostics said, "as part of our efforts to develop a vaccine against the current swine flu outbreak."

Novartis, based in Basel, Switzerland, said the research "showed a way forward" in regards to the new swine flu virus, a sample of which the company had received.

In another trial, the Aflunov vaccine was being considered safe and effective, the company said, for administration in children as young as six months of age.

The MF59 adjuvant, which increases the effectiveness of vaccines, was already approved for use in Europe in seasonal flu vaccines for people over the age of 65.

Margaret Chan, the head of the World Health Organization, said late Wednesday, after raising the pandemic influenza alert to phase 5, the second-highest, that she was in touch with pharmaceutical companies to garner their support in dealing with swine flu.

The WHO chief added that work was already in progress to develop the seed virus from which a vaccine for the new swine flu could be created and the research would be shared with drug manufacturers.

Roche, the Swiss-maker of Tamiflu, the anti-viral drug for the flu, has said it would cooperate with the WHO on supporting efforts to treat swine flu.

Chan said that while private sector was independent, businesses should act with their corporate-social responsibility.

So far "not a single company said to me 'We are not paying attention to the needs of the poor,'" the WHO chief said.

Roche said it was selling doses of Tamiflu to the developing world for 12 euros a package, 3 euros less than in the developed economies. It had also donated some 5 million doses to the WHO in 2006, around 3.5 million of which were still in stockpiles.

WHO officials said discounts on drugs may not be enough for the poorest nations. (dpa)