Comparison of an active and passive surveillance system of primary care providers for hepatitis, measles, rubella, and salmonellosis in Vermont.

Between June 1, 1980 and May 31, 1981, the Vermont Health Department telephoned a randomly chosen half of the state's primary care offices for surveillance reports of hepatitis, measles, rubella, and salmonellosis. No reports were actively solicited from the other half of the primary-care practices in the state. Active-surveillance units made more reports and more complete reports of diseases and had twice the number of reports per patient seen by the practice than did passive-surveillance units. (Am J Public Health 1983; 73:795-797.)