Benchmark 6E
The Human Organism: Physical Health
Grades K-2, page 144

Some diseases are caused by germs, some are not. Diseases caused by germs may be spread by people who have them. Washing one's hands with soap and water reduces the number of germs that can get into the body or that can be passed on to other people.

NSES Content Standard F 
Science in Personal and Social Perspectives: Personal health
Grades K-4, page 140
Individuals have some responsibility for their own health. Students should engage in personal care--dental hygiene, cleanliness, and exercise--that will maintain and improve health. Understandings include how communicable diseases, such as colds, are transmitted, and some of the body's defense mechanisms that prevent or overcome illness.