Baxter International Inc. (BAX) said Friday that it has launched full-scale production of a commercial vaccine for the A/H1N1 flu virus and that it could have it ready for use as early as July.

The World Health Organization officially declared a pandemic on Thursday for the virus, also known as the swine flu, and Baxter shares have been on the rise since amid expectations this will trigger orders between health organizations and vaccine makers, including Baxter.

The Deerfield, Ill., company said in a release that "a number of national public health authorities" have existing agreements with the company that allow them to place orders following the pandemic declaration.

"These public health authorities will be evaluating their needs to determine their orders for vaccine supply," Baxter said.

It also said it is "diligently working to deliver a pandemic vaccine for use as early as July."

Shares of Baxter, which have recently been pressured by worries about the government closely examining the medical-plasma market where Baxter is a major player, recently traded up 3% to $49.32 after climbing 3.1% on Thursday.

Baxter received a sample of the flu strain from the WHO in May. The company has a cell-based vaccine technology that it says may allow for faster production and delivery than the traditional production methods that rely on chicken eggs.

European regulators have already cleared a mock-up pandemic vaccine made by Baxter. That clearance allows for fast-track approval of a vaccine for the specific A/H1N1 strain, the company said.

-By Jon Kamp, Dow Jones Newswires; 617-654-6728; jon.kamp@dowjones.com