There are no proven therapies for the latest outbreak, which has killed at least 6,513 and sickened nearly 170,000 people worldwide since emerging from the Chinese city of Wuhan less than three months ago.

The National Institutes of Health, an agency within the Department of Health and Human Services, has been fast-tracking work with biotech company Moderna to develop a vaccine using the genetic sequence of the new coronavirus. The trial is taking place at the Kaiser Permanente Washington Health Research Institute in Seattle, Washington, where COVID-19 cases have surged and authorities have banned mass gatherings. The early-stage, or phase 1, trial will test the vaccine on 45 males and non-pregnant females between the ages of 18 and 55, according to trial details on NIH's website.

Finding "a safe and effective vaccine" to prevent infection from the new coronavirus "is an urgent public health priority," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said in a statement Monday. "This Phase 1 study, launched in record speed, is an important first step toward achieving that goal."

Hopes to get a vaccine to market are high, but doctors are setting expectations low for how quickly it can happen. Developing, testing and reviewing any potential vaccine is a long, complex and expensive endeavor that could take months or even years, global health experts say. Before researchers can begin human trials, they must have a firm understanding of the pathogen, run safety tests and find enough human volunteers.

The early-stage trial will be led by Dr. Lisa Jackson, a senior investigator at Kaiser. Study participants will receive two doses of the vaccine via intramuscular injection in the upper arm approximately 28 days apart, NIH said. Each participant will be assigned to receive a 25 microgram, 100 mcg or 250 mcg dose at both vaccinations, with 15 people in each dose cohort, the agency said.

"This work is critical to national efforts to respond to the threat of this emerging virus," Jackson said. "We are prepared to conduct this important trial because of our experience as an NIH clinical trials center since 2007."

Fauci told reporters last week a vaccine for public use likely won't be ready for another 12 to 18 months.

He said the potential vaccine by Moderna contains genetic material called messenger RNA, or mRNA, that was produced in a lab. The mRNA is a genetic code that tells cells how to make a protein and was found in the outer coat of the new coronavirus, according to researchers at the Kaiser Permanente Washington Health Research Institute.

The mRNA instructs the body's own cellular mechanisms for making proteins to make those that mimic the virus proteins, thereby producing an immune response.

Fauci told reporters last month a vaccine may not solve "problems in the next couple of months but it certainly would be an important tool that we would have." He said it's possible the virus will prove to be seasonal, thus likely to subside in the warmer months like the flu.

In the meantime, some health authorities are using Gilead Sciences' antiviral drug Remdesivir, which was tested as a possible treatment during the Ebola outbreak. CDC director Robert Redfield said at a separate hearing last week that the drug is being used in Washington state.