Dixon will be quarantined until the morning of Nov. 14 in the Harlem apartment she shares with Dr. Craig Spencer, who has been in an isolation unit at Bellevue Hospital in Manhattan since Thursday, according to a statement from the New York City Health and Hospitals Corporation.
Dixon was also quarantined there, although she hasn't shown any symptoms of the virus.
Spencer now has gastrointestinal symptoms, which health officials said was "anticipated." He was described as awake and communicating.
"In addition to the required supportive therapy, we initiated antiviral therapy within hours of admission. We also administered plasma therapy yesterday. These therapies have been used at Emory and Nebraska," city health officials said in a statement today.
Dixon's family said they are confident in the medical care Spencer is receiving.
"The Dixon family is asking for your thoughts and prayers for Craig Spencer and his fiancee, our daughter, Morgan Dixon," read the statement.
Dixon, 30, is a development associate at the Hope Program in Brooklyn, which helps homeless and other disadvantaged adults find and keep jobs.
She will have a security detail outside her apartment at all hours and will be periodically visited by a member of the city health department, but she will be the only one staying at apartment, city officials said.
She has been given an iPad to communicate with family members and authorities, and will be provided free food during her time in quarantine, they said.
The Dixon family said they have not had physical contact with their daughter or Spencer, 33, since his return to New York from Guinea.
Two friends of Spencer are also under quarantine at home until Nov. 14. Neither has shown symptoms of the virus.
Spencer became the fourth person to be diagnosed with Ebola in the United States after he was hospitalized Thursday. He developed a fever that morning and alerted authorities, who transported the doctor from his Harlem apartment in a specially designated ambulance.
"We have confidence in the medical care Craig is receiving and we are hoping for a complete recovery," the Dixon family said.
"We are very proud of and support the work Craig has been involved with throughout this career," the Dixon family said.