On top of cleaning rooms, schools are posting signs reminding students to cover their coughs and sneezes.
On-campus vaccinations are part of a plan proposed to combat the swine flu for the upcoming school year.
The outbreak forced county health officials to shut down local schools in May.
The county's chief public health officer has asked school officials to shut down schools when 30 percent of students are absent because of flu and to consider allowing trained volunteers and medical professionals to give swine flu shots on campus.
Superintendents are expected to make a decision about on-campus vaccinations by August 12.
If you're feeling sick, with flu-like symptoms, you are encouraged to stay home from work or school and contact your doctor.
For information regarding the swine flu virus, visit the County website or call 211 San Diego.
The Centers for Disease Control and Prevention hopes to have a swine flu vaccine by October. Kids over the age of 6 months, pregnant women and health care providers are expected to be given priority when the 120 million doses of the vaccine become available.