The swine flu is a new flu virus and people have little or no immunity. If this new flu virus begins to spread easily person-to-person, it could sweep across the country and around the world in a very short time. This would cause an influenza pandemic.
At this time, we do not know how serious it will be or how long it will last. As more people become infected, the risk of exposure to the public becomes greater.
San Mateo County Public Health Department:
Information is also available online: