As the United States moves past its first Covid-19 peak, public health experts and tech companies are pressing ahead with the latest strategy intended to control the new coronavirus' spread throughout America: contact tracing.

States across the country have been laying the groundwork to launch massive contact tracing efforts to identify people who may have contracted the virus, and some public health experts have said the efforts are crucial to preventing another spike in Covid-19 cases as states continue relaxing social distancing measures intended to curb the epidemic.

But there's one big obstacle that could derail the contact tracing effort: Many Americans don't like it. So does that mean the efforts are doomed?

What is contact tracing?

Currently, there are two different types of contact tracing efforts that have been gaining momentum—and American's attention—in the United States.

The first involves efforts by a majority of states to increase testing for the new coronavirus and hire thousands of human contact tracers. Under these efforts, human contact tracers quickly reach out to so-called "index patients," or a person who tested positive for the new coronavirus, within 24 hours of the diagnosis. Then, contact tracers determine how long the index patient was infectious by figuring out how much time passed since the patient was initially infected with the virus.

Next, contact tracers interview the index patient to find out how many people the index patient had contact with during their infectious period. Contact tracers then work to locate those contacts, inform them that they were exposed to the new coronavirus, and recommend they self-isolate for 14 days to prevent them from exposing others.

The final step is for contact tracers to follow up with the contacts to see if they are developing symptoms of Covid-19 and instruct them to consult with a physician as needed. If a contact ends up testing positive for the new coronavirus and reveals that they made their own contacts during their infectious period, tracers begin the process all over again, with that patient now serving as the index case.

The second type of contact tracing effort that's been gaining momentum relies on technology such as online apps or smartphone data to assist with contact tracing.

For example, Apple and Google this week began to roll out a tool that uses Bluetooth on people's smartphones to alert them if they might have been within close proximity of someone who has tested positive for the new coronavirus. The companies said the tool requires people to opt in before it begins working. Once they do, their phone will create a unique, anonymous code that is sent using Bluetooth Low Energy signals to any other phones nearby—which store a log of these codes and when they received them. If a person receives a positive test for the new coronavirus, they can submit their ID code as positive to a central database. All other phones will then check back in to the database and see if there's a match to an infected person. If so, the user will get an alert saying they've potentially been exposed to the virus.

For the first phase of Apple's and Google's new project, users need to download a third-party app built by state-level health agencies to participate. For the project's second phase, the tech companies will seek to build the tool into their underlying platforms, allowing users to toggle on participation in their phones' settings. Apple and Google have said the companies will not allow government institutions to access any location or personal data collected from users and their phones.

States and health care institutions also have rolled out separate smartphone apps that work in a similar manner. People must download the apps to their phones and input information about their infection status. Some of the apps allow contact tracers to use the data to get in touch with other users that may have come in contact with an infected person or examine relationships between events, places, and people so they can identify potential outbreaks and their origins.

According to a survey by NPR, about half of states have considered using online apps or smartphone data to assist with contract tracing. Ashley Ford, a managing director at Advisory Board, said states likely will look to use a combination of both human contact tracers and apps for their efforts.

Many Americans are resistant to contact tracing

Although public health experts say the contact tracing efforts could help states safely ease social distancing measures and contain the country's Covid-19 epidemic, many Americans have privacy concerns about the efforts and appear unlikely to participate.

Specifically, an Axios-Ipsos Coronavirus Index poll conducted from May 8 to May 11 found that 68% of respondents said they were not at all or not very likely to participate in contact tracing conducted by the federal government, 66% said they were not at all or not very likely to participate in contact tracing conducted by major tech companies, and 63% said they were not at all or not very likely to participate in contact tracing conducted by cell phone and internet providers.

Those sentiments aren't surprising given recent backlash against tech companies' privacy policies, and some U.S. policymakers have expressed similar skepticism.

But Americans' participation in contact tracing is crucial to the efforts' success. Research suggests 60% of a population must participate in contact tracing in order for the efforts to effectively mitigate the new coronavirus' spread. However, that percentage may prove difficult to reach. In Singapore, for example, adoption of a contact tracing app is hovering around 25%.

Is there a path forward?

But that doesn't mean contact tracing efforts in the United States are completely doomed.

Americans seem to be more open to working with human contact tracers than they are to using apps or offering up their smartphone data for such efforts—particularly if the contact tracing efforts are established by health officials in their local areas.

The Axios-Ipsos Coronavirus Index poll conducted from May 8 to May 11 found that 51% of respondents said they were somewhat or very likely to participate in contact tracing efforts led by CDC and public health officials. Further, the latest Axios-Ipsos Coronavirus Index survey found that 76% of respondents said they'd be willing to give contact tracers a list of all the people they've recently come into contact with if they test positive for the new coronavirus—if the contact-tracing effort is locally run and conducted in person.

What's more, 84% of respondents said they'd be willing to self-quarantine for 14 days if someone from a locally run contact-tracing effort notifies them that they've come into contact with someone who tests positive for the virus, and 59% said they'd be willing to undergo weekly testing to help track the virus' spread. Further, 56% of respondents said they'd be willing to give local contact tracers access to their cell phone location data if they test positive for the virus.

Carolyn Cannuscio, an associate professor of family medicine and community health at the University of Pennsylvania's Perelman School of Medicine who is leading a contact tracing effort in Philadelphia, told the Philadelphia Inquirer's Tom Avril that many patients are eager to contribute to the process. "People who are sick don't want others to suffer," Cannuscio, said. "I think there's probably some healing potential there."

But ultimately, the success of contact tracing "depends on the goodwill of a population," ProPublica's Caroline Chen writes. And that raises another issue: the long-standing conflict between Americans' individual rights and the "common good," the Associated Press's Ted Anthony notes. Lenette Azzi-Lessing, a clinical professor of social work at Boston University, told Anthony, "The pandemic and dealing with it successfully does require cooperation. It also requires shared sacrifice. And that's a very bitter pill for many Americans to swallow."

Still, Jeremy Konyndyk, a senior policy fellow at the Center for Global Development, expressed optimism that Americans are willing to sacrifice some of their individual liberties to ensure others' safety. "I think it's reasonable to expect that while there may be some resistance to tracing and quarantine, the majority of people will accept it."