A public health expert who led the fight against the Ebola outbreak in Liberia says the United States is downplaying one strategy key to stopping the coronavirus pandemic: contact tracing.

Tolbert Nyenswah, senior research associate at the Department of International Health at the Johns Hopkins’ Bloomberg School of Public Health, thinks successful contact tracing could reopen the country within two to three months.

“By now, 100% of all people coming in contact with COVID-19 patients must be traced,” he said. “Even one missed contact can keep the outbreak going on and on and on.”

According to a report released last week by researchers at the Johns Hopkins Center for Health Security, the nation needs a new workforce of 100,000 contact tracers. At that scale, the effort would require $3.6 billion, researchers projected. They called for an infusion of emergency funding from Congress.

Their estimates are based on what has worked in other countries. In the Wuhan, China region where the outbreak started, 9,000 contact tracers were rapidly deployed to curb the spread in thecity of 11 million.

The World Health Organization breaks down contact tracing into three basic steps: identification, listing and follow-up.

Once a patient tests positive for the virus, contacts are identified by asking who the patient came in contact with, such as family members, colleagues, friends or health care providers. Then tracers attempt to identify and reach out to all those who came into contact with the COVID-19 positive patient. Regular follow-ups should be conducted with all contacts to monitor for symptoms.

Even with U.S. cases surpassing 630,000 as of Friday afternoon, Nyenswah thinks contact tracing down to the last household is still possible. 

“For us to get ahead of the curve, for us to flatten the curve, for us to bend the curve, to stop the outbreak … contact tracing, contact tracing, contact tracing,” said Nyenswah, recounting the extreme efforts of trackers in rural Africa compared to a first-world nation like the U.S.

“It’s cumbersome, it’s painstaking, it might take a long time to do it,” he added. “It can be done.”

Not everyone agrees so wholeheartedly. Matthew Fox, professor of epidemiology and global health at Boston University, is in favor of contact tracing, but doesn’t thinkthe U.S. can get down to zero cases before a vaccine is available in the next few years.

“I think it’s being downplayed in the media but I don’t think it’s going to be the solution to all our problems,” he said. “We think coronavirus is far more transmissible. Ebola you need to come in contact with bodily fluids … droplet transmission is so much harder.”

Tech giants: Apple and Google team up on coronavirus tracking technology

Trump wants to reopen America: Federal health officials warn the bar to do so safely may be too high

However, Fox said contact tracing plays an important part in a broader strategy incorporating other public health measures to minimize transmission. Although it won’t make much of an impact now as cases in the country continue to climb, he said it’s important to start scaling up contact tracing for when cases numbers become more manageable.

John Welch, Director of Partnerships & Operations for Massachusetts COVID Response for Public in Health, is hiring about 900 contact tracers for the state. 

Public in Health – a nonprofit global health organization – estimates those people will make about 80,000 to 100,000 calls a week working 12 hours a day for all seven days. Welch said contact tracers will not only be keeping track of contacts, but will be redirecting patients in need to the proper resources for testing or treatment.

Welch has seen these efforts work firsthand in Sierra Leone during the Ebola epidemic. He choked up remembering when he couldn’t imagine a day the outbreak would end.

“I wept when it was over because you can’t imagine sitting in the middle of it looking around and thinking, ‘When does it end?’” he said. “But it ends by doing this stuff.”  

Contributing: Letitia Stein and Brett Murphy, USA TODAY. Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.