Contact tracing is a recognized public health measure for controlling the transmission of infectious diseases. It entails locating, isolating, and managing individuals who have an infectious disease, identifying individuals that they have come in contact with, and quarantining those individuals and referring them to testing and other relevant interventions. Contact tracing has received intense attention due to the COVID-19 pandemic and the hundreds of millions of cases reported to date. It has been a critically important tool to monitor the spread of infection and to interrupt the potential for the ongoing spread of disease.
In a new article published in the American Journal of Public Health, PRI Co-Principal Wafaa M. El-Sadr, MD, MPH, MPA discusses contact tracing, its history, barriers, facilitations, and evolutions. El-Sadr also provides insights for future programming and research. The article was written with support from Columbia ICAP’s Joey Platt, MPH, Melanie Bernitz, MD, MPH, and Melissa Reyes, MPA. Below is a summary of the article which includes segments of the original text.
There is a long history of using contact tracing in public health, the article explores its use in syphilis and other sexually transmitted infections (STIs), HIV, tuberculosis, Ebola virus disease, and COVID-19. Contact tracing and partner notifications (process by which the sexual contacts of a patient with an STI are informed that they may be at risk) have been an important tool for controlling transmission of these infections over the past century but have had controversial origins that are particularly relevant to concerns about stigma. For example, in the case of people living with HIV, overall, stigma and discrimination as well as punitive laws and repressive policies have hindered voluntary partner notification.
The history of contact tracing highlights the important role that individuals, societies, and the health system can play in safeguarding public health.
The article identifies several barriers and facilitators that influence the feasibility and effectiveness of contact tracing. The characteristics of the specific condition, the duration of the disease (i.e., chronic vs acute) and time from exposure to symptom onset (i.e., incubation period), wide access to testing, and the effect of stigma all play a role in the success or failure of contact tracing. Determining whether contact tracing is successful at reducing transmission is typically measured by applying epidemiological assumptions to programmatic outcomes. These measures include using the number of case investigations within a specific period, the number of contacts provided by cases and percentage notified of exposure within a specific period, and the number of cases and contacts who complete isolation and quarantine.
The authors end the article by recommending that society takes the lessons learned from the COVID-19 pandemic and examine “how best to support and conduct contact tracing, how to tailor it to specific conditions, how to ensure the confidentiality of information collected, and how to prioritize those most at risk and provide them with the support they need to adhere to public health guidance.”
The full article can be read at the American Journal of Public Health.