To better trace the spread of coronavirus, Singapore and China have been using apps that collect data about citizens' whereabouts and let people know if they've potentially been in contact with someone who has been diagnosed with the virus. Now, similar apps are being piloted in New York and Massachusettes in an attempt to better "understand more about the clinical course of the disease."

The CDC’s Epidemic Intelligence Service Program trains individuals how to perform contact tracing in order to help slow the spread of infectious diseases. Success from this strategy has been reported in South Korea regarding the coronavirus, and now the U.S. officers are deploying to find out more about "how contagious it is, how it spreads, the severity of the illness, what groups are most likely to be affected."

When coupled with long-term state investment in public institutions, a rapid response to a pandemic is most effective. In India, Kerala state acted quickly relative to its neighbors in communicating risks, tracking cases, testing, and requiring quarantines for tourists. The effectiveness of the measures benefitted from the states'investment in education and public health institutions.

In an effort to contain the coronavirus, Alaska nurses are stepping in as "contact tracers," as a means of investigating who should be quarantined or tested. The initiative has been credited for helping keep Alaska's rate of transmission low thus far in addition to other measures such as social distancing.

When the Ebola virus struck Nigeria and Senegal the governments of both countries took several steps to prevent an outbreak. Both countries responded to the first reported case quickly, traced all of the people that the patient had come into contact with prior to diagnosis and monitored them twice daily for signs of the virus. This public health campaign aimed to dispel fear and educate communities on prevention of Ebola.

China and South Korea were the first two countries to emerge as possible models for how to contain coronavirus. While critics have called China's tactics Draconian, they are praising South Korea for implementing "swift action, widespread testing, and contact tracing," and including their citizens in their approach.

Some of the governments that have had the most success in getting a handle on the spread of the coronavirus have used individual location data to conduct contact tracing and track the spread of the virus. However, some in Europe and the United States worry these tools violate privacy rights, even in the midst of a public health crisis.

In Philadelphia, volunteers with the University of Pennsylvania have launched a small-scale effort in contact tracing, a method in which disease detectives track and monitor the interactions and movements of known infected people. Both time- and labor-intensive, contact tracing is most effective on the front end of an outbreak, when there are fewer cases. The university has trained a few dozen volunteers, though limited access to testing and violations of privacy remain concerns.

While East Asian countries have found success in deploying technology to do contact tracing, or a method of virus containment in which disease detectives track and monitor the interactions and movements of known infected people, U.S. states like Massachusetts is relying on people power. In a $44 million program, the state government is hiring more than 1,000 tracers. San Francisco is using 150 volunteers, and Ireland is sending out 1,000 furloughed government workers.

As a method known as contact tracing, in which disease detectives track and monitor the interactions and movements of known infected people, has been hailed as a success in countries like South Korea, the United States has begun to employ the technique as it considers reopening parts of the economy. Relying heavily on widespread testing, contact tracing is already being used in Massachusetts, where an organization called Partners for Health trained 300 volunteers as contact tracers.