The federal government is considering altering the protocols for doctors and health-care workers who return to the United States from West Africa, authorities said Friday.

“It’s one of the questions the federal government is thinking through,” New York Gov. Andrew Cuomo (D) told Fox 5 in New York.

A federal official said that the idea of quarantining medical workers who participated in the Ebola response in West Africa was being considered, but said no decision had been made.

While the idea of a quarantine is being considered, Josh Earnest, the White House press secretary, emphasized that officials are still determining whether it is medically justified.

“These kinds of policy decisions are going to be driven by science,” he said.

The possible change would come in the wake of Thursday’s diagnosis of Craig Spencer, a doctor who had treated Ebola patients in Guinea, one of the countries at the heart of the Ebola epidemic.

Spencer, 33, returned to the United States last week and began feeling ill on Tuesday. He was taken to Bellevue Hospital on Thursday after reporting a fever of 100.3 degrees that morning and gastrointestinal problems.

But as federal officials consider a possible change, authorities in the New York area announced that they would take more immediate action. Medical personnel returning to New York and New Jersey from the Ebola-riddled countries in West Africa will be automatically quarantined if they had direct contact with an infected person, officials announced Friday.

New York Gov. Andrew Cuomo (D) and New Jersey Gov. Chris Christie (R) announced the decision at a joint news conference Friday at 7 World Trade Center.

“The steps New York and New Jersey are taking today will strengthen our safeguards to protect our residents against this disease and help ensure those that may be infected by Ebola are treated with the highest precautions,” Cuomo said in a statement.

They said that public-health officials at John F. Kennedy and Newark Liberty international airports, where enhanced screening for Ebola is taking place, would make the determination on who would be quarantined. Anyone who had direct contact with an Ebola patient in Liberia, Sierra Leone or Guinea will be quarantined.

In addition, anyone who traveled there but had no such contact would be actively monitored and possibly quarantined, authorities said.

Laurie Garrett, a senior fellow for global health at the Council on Foreign Relations, said in an interview that while it made sense for returning medical workers to take voluntary steps to isolate themselves upon their return to the United States, concern over Ebola’s transmission in the West had begun to interfere with volunteers’ ability to contain the outbreak at the source.

“For everybody that’s professionally trying to go to the three epidemic countries, the situation has become more difficult with each passing day and each Ebola case — or alleged Ebola case — named in the United States,” Garrett said. “We’re in a crisis actually that imperils the entire effort to stop the epidemic that is completely about the fear of countries that have no known epidemic.”

Not only have many airlines curtailed flights to the three countries most affected by Ebola, Garrett noted, but nearly every major insurance carrier has now canceled medevac coverage for individuals choosing to travel there.

“This whole right of return issue, and circumstances of return, is fluid,” she said. “We’ve hit the point where it is quite obviously affecting the recruitment of volunteer health workers.”

Experts say that the region needs roughly 19,000 health and logistics personnel to contain the epidemic; outside of military personnel, total foreign volunteers now number in the hundreds.

Still, Garrett added, any people traveling to a nation affected by Ebola should undertake efforts to isolate and monitor themselves for any symptoms of the disease for 21 days after returning to their home country.

“At this point it’s incumbent on anyone going over there to build into your plans the assumption that you will have to radically modify how you live and work upon your return for three weeks,” she said.

Spencer had gone to Guinea to work with Doctors Without Borders, the international relief group that has been on the front lines of the public health crisis.

On Friday, the group said Spencer had followed its protocols for people returning from Ebola work, which included regular health monitoring.

“Extremely strict procedures are in place for staff dispatched to Ebola affected countries before, during, and after their assignments,” Sophie Delaunay, the group’s executive director, said in a statement. “Despite the strict protocols, risk cannot be completely eliminated. However, close post-assignment monitoring allows for early detection of cases and for swift isolation and medical management.”

The precise nature of Spencer’s infection is being investigated, the group said. So far, two dozen people working for the organization have fallen ill while fighting Ebola, and 13 of them have died.

Tim Shenk, a spokesman for Doctors Without Borders, said Friday afternoon that quarantining all medical workers who return from West Africa “would be an excessive measure to take at this stage.”

“As long as a patient hasn’t developed symptoms, the risk of contamination is close to zero,” he said.

Spencer became just the fourth person diagnosed with Ebola in the United States and the first outside Texas, which has previously been the nexus of Ebola infections in the country. Thomas Duncan, a Liberian man who flew to Dallas, was diagnosed last month and died eight days later. Two nurses who treated Duncan were infected while caring for him. No one who had close contact with Duncan or the nurses has tested positive for Ebola so far.

The two nurses who contracted Ebola in Dallas were both declared virus-free this week. One was cleared on Wednesday, while Nina Pham, the other nurse, left the National Institutes of Health on Friday morning after doctors determined she no longer had the virus.

President Obama on Friday wanted to meet with Pham “to thank her for her service,” Josh Earnest said at his daily White House briefing.

When White House officials found out early Friday that Pham would be released, Earnest said, they contacted the NIH “to let her know that the president was interested in meeting her if she felt up to it.”

Pham did not undergo any additional medical testing before greeting—and hugging—the president, Earnest said, noting that she had been shown to be free of the virus on five separate occasions before being released.

Earnest also provided new details Friday about the coordination between federal and New York state officials after Spencer fell ill Thursday. President Obama ordered the Pentagon to provide an aircraft to transport a team of experts from the Centers for Disease Control in Atlanta to New York City’s Bellevue Hospital so they could get there “as soon as possible,” he said.

The team, which helped supervise the protocols for treating Spencer, arrived “within a couple of hours” of his arrival, Earnest added.

“We certainly are pleased that so much of the planning that’s been done in recent days has proved to be useful,” Earnest said of how Bellevue’s handled Spencer’s admission.

While federal officials are discussing the idea of quarantining medical professionals upon their return to the United States, Earnest emphasized that officials are still determining whether it is medically justified.

“These kinds of policy decisions are going to be driven by science,” he said.

The administration is focused on protecting the American public, Earnest said. “But at the same time we don’t have to overly burden those individuals who are going to great lengths to stop this outbreak at the source,” he added.

Earnest also emphasized that these aid workers are aware of the public health concerns stemming from their service.

“Individuals who have spent time in West Africa certainly understand the seriousness of this disease,” he said, adding at one point of the precautions Spencer took upon his return to New York, “He is a highly trained medical professional [and] certainly had the capacity to take his own temperature.”

White House officials continued to emphasize the low probability of an Ebola outbreak in the U.S. Earnest said Obama would “have no qualms” about riding the New York subway, visiting the High Line or visiting a Brooklyn bowling alley even in the aftermath of Spencer’s diagnosis.

“The fact is, the risk facing the average New Yorker is exceedingly low,” he said.

Spencer works at New York-Presbyterian/Columbia University Medical Center. On Thursday, the hospital called him “a dedicated humanitarian” who “always puts his patients first.” The hospital said in a statement that he had not been to work and had not seen patients since returning from overseas.

On Tuesday, two days before he was hospitalized and diagnosed, Spencer went to a bowling alley in Williamsburg, rode three New York subway lines and used an Uber car. The bowling alley had closed after Spencer’s diagnosis, while Uber said that health officials had told them the car’s driver and any subsequent passengers were not at risk.

Spencer was is in stable condition Friday, authorities said, and he is talking to public-health workers as they try to trace his steps in recent days. Even as “disease detectives” work to determine who Spencer may have encountered and check the coffee shops and restaurants he visited, officials stressed that they felt they had the situation contained and urged calm among residents.

“New Yorkers who had not been exposed to an infected person’s bodily fluids are simply not at risk,” New York Mayor Bill de Blasio said during a briefing Friday afternoon. “There is no reason for New Yorkers to change their daily routine in any way.”

Spencer “poses no threat to others,” de Blasio said.

The ongoing treatment for Spencer at Bellevue Hospital involves giving him fluid and electrolytes and monitoring his vital signs, said Ram Raju, head of the city’s Health and Hospitals Corporation. Spencer remains in good enough shape to talk on the phone and tell the disease detectives from the health department about his steps so far this week.

Cuomo on Thursday had said that Spencer was a medical professional who had seen Ebola up close, adding that the doctor had been monitoring himself and immediately recognized the symptoms.

“He was familiar with the possibility and the circumstances, so he handled himself accordingly,” Cuomo said.

New York officials repeatedly emphasized on Thursday and Friday that they were prepared for Ebola’s arrival, having trained while also preparing Bellevue and other hospitals for handling patients with the virus.

The office of New York Mayor Bill de Blasio (D) posted images of him riding the subway on Friday morning in an attempt to show residents that they had nothing to fear from public transportation:

Rep. Darrell Issa, a California Republican who chairs the House Oversight and Government Reform Committee, urged the Obama administration on Friday to take steps to improve what he characterized as a “bumbling” response to the Ebola crisis.

“I think we all know that the system is not yet refined to where we could say it is working properly,” he said during a hearing on the U.S. government’s response to the disease.

Issa and other members of Congress questioned the measures taken by the administration to prepare for a possible pandemic before Ebola appeared in U.S. hospitals, as well as what officials have done since then to ensure the disease doesn’t spread.

Nicole Laurie, a senior official at the Department of Health and Human Services, said Friday that the risk of a significant Ebola outbreak in the United States was “remote.”

But health-care workers who will be the first to respond to Ebola cases in the United States were worried, particularly after two nurses contracted the disease through an exposure that has still not been explained.

Deborah Burger, co-president of National Nurses United, said these workers remain at risk. She said nurses have received inconsistent instructions, were often left to make decisions about proper precautions for themselves, and at times were forced to improvise their own protective gear because their medical facilities were unprepared. She said only new, legally required guidelines would ensure that medical facilities would provide workers the protection they need.

“The response to Ebola from U.S. hospitals and governmental agencies has been dangerously inconsistent and inadequate,” she said. “The lack of mandates and shifting guidelines from agencies and reliance on voluntary compliance has left caregivers uncertain, severely unprepared and vulnerable to infection.”

Ed O’Keefe, Lena Sun and Missy Ryan contributed to this report.

[This post has been updated. First posted: 10:54 a.m.]