Gaithersburg, Md.-based MedImmune, the global biologics arm of AstraZeneca, is restructuring its infectious disease and vaccines research, development and operations, closing its Mountain View, Calif., and Santa Clara, Calif., sites and consolidating its infectious disease and vaccines R&D to other existing sites. The changes are expected to be completed in 2014.

MedImmune's Hayward, Calif., site will remain open with additional capabilities invested in it.

MedImmune said the changes will enhance innovation across its therapeutic areas and improve alignment with other areas of product development while reducing the fixed costs associated with the sites.

The company estimates that approximately 300 positions will be affected. Of those, approximately 100 positions will move to other MedImmune locations. Worldwide, MedImmune has approximately 3,500 employees.

In February 2012, AstraZeneca announced an efficiency program to improve productivity, foster innovation and strengthen the company's commercial, operations and R&D capabilities, which runs through 2014.