According to StreetInsider.com, the following companies may benefit from protection, therapy and/or vaccination against swine flu.  Most of these are highly speculative so trade at your own risk.

Alpha Pro Tech (APT) – protects people with disposable protective apparel such as masks.

Generex Biotechnology (GNBT) – developing drug delivery systems.

Hemispherx BioPharma (HEB) – engaged in drug therapies for viral and immune based chronic disorders.

BioCryst Pharmaceuticals (BCRX) – develops drugs that block enzymes involved in cancer, viral infections and autoimmune diseases.

AVI BioPharma (AVII)- developing of ribonucleic acid (RNA)-based drugs targeting a range of diseases.

Sanofi-Aventis (SNY) – pharmaceuticals and human vaccines through sanofi pasteur.

CombiMatrix Corporation (CBMX) – develops molecular diagnostics, nanotechnology and defense, and homeland security markets.

Gilead Sciences (GILD) – could benefit from TamaFlu sales.

Off the top of my head I can think of 3 companies that might be hurt by swine flu fears ..

Sanderson Farms (SAFM), Zhongpin (HOGS), Tyson Foods (TSN)

The airlines could very well be hit as well Alaska Airlines (ALK), AMR, Delta (DAL), Southwest (LUV), Continental (CAL), Allegiant (ALGT)