China's State Food and Drug Administration (SFDA) gave the green light on September 03 for the Panflu vaccine, which Sinovac says needs only one 15 microgram dose to be effective.

Worldwide, pharmaceutical firms are in a race to produce vaccines against H1N1 before the northern hemisphere winter, when experts warn the flu could spread wider.

Sinovac was the first company worldwide to complete clinical trials for a vaccine to treat the new strain of H1N1, commonly dubbed swine flu.

"At the beginning of this year, we forecast our sales would rise by 20 percent," CEO Yin Weidong said yesterday. "Looking at things now, H1N1 has given us an opportunity, so the rise should be more than 20 percent," he said.

A vaccine produced by Chinese rival Hualan Biological also passed muster by a panel of experts this week, while, in Europe, Novartis said its vaccine gave a strong immune response after one dose in a pilot trial.

Australia's CSL Ltd said it had completed its first batch of 2 million shots in 15 microgram doses. CSL is producing up to 1.5 million doses per week until it fills orders, including an order for 21 million doses from the Australian government and $180 million of orders from the US.

Sinovac's US-listed shares have risen 77 percent in the last two weeks and hit a historic high of $12.45 on Tuesday, on anticipation it would be able to produce and sell its vaccine to China's vast population.

"I'm very happy to see that investors, since we passed the first stage, have been supporting us in producing this product and opening up this market," Yin said.

Shenzhen-listed Hualan has gained 44 percent in two weeks, hitting a life high on Monday - and rose 8 percent yesterday.

The Chinese government has said it plans to have enough vaccine to cover 5 percent of its 1.3 billion population by the year-end.

Sinovac has hurried its Panflu vaccine into production while completing the Chinese approval process. It expects to begin supplying the government with vaccines this month, for allocation to health workers and other priority groups.

Panflu is approved for people over 3 years old.

"Of the 1,600 volunteers testing the vaccine for safety and effectiveness, 10 percent had an adverse reaction," Yin said.

"These were mostly minor, for instance fevers, weakness, normal things like that. So far, there have not been any serious or abnormal reactions reported."

The SFDA had ordered the company to continue monitoring reactions during the mass production stage, and it plans to continue evaluating the effectiveness and safety, he added.

Originally known for its hepatitis vaccines, Sinovac is expanding capacity to 30 million doses a year, from 20 million, to meet demand for H1N1 vaccines, Yin said.

Sinovac's vaccine can be produced for about 30 percent less than similar products in Europe, Yin said, an advantage the company says will help make vaccines available to those who need them.

Yin said Sinovac would try to supply other countries that need the vaccine, but he did not elaborate.

The company already has a preliminary agreement for South Korea's Boryung Pharm Co Ltd to represent it in registering the vaccine there.

Yin said Sinovac hopes some day to market Panflu in Europe, but would have to go through a lengthy approval process.

There have been no deaths from H1N1 in China and only one severe case, in the southern province of Guangdong.