BEIJING - Chinese vaccine maker Sinovac Biotech Ltd said on Tuesday that it had received an additional order for 5.19 million doses of its H1N1 influenza vaccine from the Chinese government.

Sinovac said in a statement it was required to produce the new batch of the Panflu.1 vaccine for the central government by Dec. 12.

The company added that it had already completed production of its first batch of 6.3 million doses.

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

China has to date reported 35,664 H1N1 infections, including three deaths. Health Minister Chen Zhu warned last month that China faced a grim situation in containing the disease as schools started up again and the number of cases rose.

Sinovac said in September that its vaccine protected patients with a single dose.