What is Contact Tracing?
Contact tracing is a measure well-known in public health to control contagious diseases (1). It is a procedure that starts when an infected individual is identified or an outbreak starts. It involves tracking each contact of each infected individual to identify, test, and treat potential exposures and to isolate the infected individuals.
Does Contact Tracing Work and Why is it Important?
Contact tracing helps to control and fight emerging infectious diseases. It helped with the eradication of smallpox by early detection of infected individuals through highly effective campaigns (1). Contact tracing was also used in recent fights against SARS in 2003 (2), and Ebola (3,4). Over 50% of COVID-19 patients are asymptomatic (5). Asymptomatic transmission of the disease has been one of the most challenging barriers to control this disease. Contact tracing and detection of asymptomatic carriers is the key to control further outbreaks while lifting the lockdown.
As the US prepares to reopen from the lockdown due to the pandemic, the US legislature (6) and many states push for increased efforts to prevent and limit another wave of the disease. The efforts mainly include increased testing and establishing a robust contact tracing plan. The Centers For Disease Control And Prevention (CDC) provided guidance to help health departments, states, and other municipalities implement contact tracing in order to respond to any increased outbreaks during the reopening of the country. This guidance is supported by efforts by many federal, private, and academic organizations (7). Until a vaccination or an effective treatment is found to fight COVID-19 pandemic, prophylactic efforts that include early detection and contact tracing to contain the disease remain the mainstay to ensure a successful control.
How is it Implemented?
Contact tracing is implemented by trained volunteers or public health workers, such as epidemiologists, to quickly identify and provide support to those who may have come in close contact with someone who tested positive for COVID-19. The CDC defines a close contact as any individual within 6 feet of an infected person for at least 15 minutes (7). A contact tracer will contact this individual and ask detailed questions to be able to determine who may be at risk of infection. The contact tracer will protect the privacy of the person who had COVID-19 by not providing details on the encounter. Once the individuals are identified who were in contact with those who tested positive for COVID-19, they will be asked to quarantine for 14 days and monitor for symptoms of COVID-19. If they do develop symptoms, they will be tested if possible, and linked with a health care provider for symptom management and further treatment, as needed. It is important for the individual in quarantine to isolate themselves from others to prevent the possible spread of COVID-19, including from those in their households. This includes asking the infected individual to use separate household items, such as separate dishes and glasses, to sleep in an area separate from other household members, and to wash their laundry separately. It is additionally important to wash their hands often and clean surfaces that they use. As new information arises regarding COVID-19, the details of contact tracing may be revised. Contact tracing is a critical tool in preventing the spread of COVID-19 and identifying those who need further support.
2. Donnelly CA, Ghani AC, Leung GM, Hedley AJ, Fraser C, Riley S, et al. Epidemiological determinants of spread of causal agent of severe acute respiratory syndrome in Hong Kong. The Lancet. 2003 May 24;361(9371):1761–6.
3. Swanson KC, Altare C, Wesseh CS, Nyenswah T, Ahmed T, Eyal N, et al. Contact tracing performance during the Ebola epidemic in Liberia, 2014-2015. PLoS Negl Trop Dis. 2018 Sep 12;12(9):e0006762–e0006762.
4. World Health Organization. Regional Office for Africa. Contact Tracing During an Outbreak of Ebola Virus Disease [Internet]. Brazzaville: World Health Organization; 2014. Available from: https://apps.who.int/iris/handle/10665/159040
7. CDC. Contact Tracing [Internet]. Centers for Disease Control and Prevention. 2020 [cited 2020 Jun 1]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/php/open-america/contact-tracing-resources.html