Contact tracing has been used for decades to control endemic contagious diseases.[Hethcote HW,
Yorke JA. Gonorrhea Transmission Dynamics and Control. New York, NY. Springer-Verlag; 1984] It
is done after disease reporting or involuntary testing identifies an individual as having a
communicable disease. An investigator interviews the patient, family members, physicians, nurses,
and anyone else who may have knowledge of the patient's contacts; anyone who might have been
exposed; and anyone who might have been the source of the disease. Then the contacts are
screened to see whether they have or ever have had the disease.
Many persons object to contact tracing as an invasion of privacy. It may be, but only in a very
limited sense. Contact- tracing interviews are always voluntary; there is no legal coercion to divulge
the names of contacts.[Woodhouse DE, Muth JB, Potterat JJ, Riffe LD. Restricting personal
behaviour: case studies on legal measures to prevent the spread of HIV. Int J STD AIDS.
March/April 1993;4(2):114- 117.] A more serious objection, especially with venereal diseases, is
the risk of breaches of confidentiality. As a matter of law, the courts do not consider the risk of
such breaches of confidentiality to be sufficient reason to restrict contact tracing. As a matter of
public health practice, there have been no significant breaches of the confidentiality of public health
records.[Guide to Public Heath Practice: Principles to Protect HIV-Related Confidentiality and
Prevent Discrimination. Washington, DC: Association of State and Territorial Health Officers; 1988]
When suspected breaches of confidentiality have been investigated, they are usually traced back
to the patient's own disclosures or to those of people whom the patient has told of the condition.
It has also been argued that contact tracing is not legally justified because it is too expensive or
because it is ineffective. The courts have rejected these arguments because contact tracing is
indeed highly efficient in finding infected persons.[Potterat JJ, Spencer NE, Woodhouse DE, Muth
JB. Partner notification in the control of human immunodeficiency virus infection. Am J Public
Health. 1989;79(7):874(3)] This was best demonstrated in the campaign to eradicate smallpox,
which was controlled not by universal immunization but by extensive contact tracing to find infected
individuals.[Carrell S, Zoler ML. Defiant diseases: hard-won gains erode. Med World News.
1990;31(12):20(7)] Fellow villagers and tribal members were encouraged in various ways to identify
infected persons. When people with smallpox were identified, they were quarantined and everyone
in the surrounding community or village vaccinated. In this way, smallpox was eventually reduced
to isolated outbreaks and then eradicated.
