BOSTON (MarketWatch) -- Chinese vaccine maker Sinovac Biotech Ltd. SVA, said it has begun production of a vaccine to prevent the H1N1 virus, also known as the swine flu. The company said it is currently able to produce up to 30 million doses of pandemic vaccine per year, and hopes to combine the H1N1 virus into a broader pandemic vaccine known as Panflu. Sinovac added that the number of doses it is able to manufacture will depend on how the H1N1 virus batches perform.