An Israeli scientist works at a laboratory at the MIGAL Research Institute in Kiryat Shmona in the upper Galilee in northern Israel on March 1, 2020 where efforts are underway to produce a vaccine against the COVID-19 coronavirus adapted from another for infectious bronchitis virus.

The vaccines are still a long way away from being available for public use, WHO officials cautioned. Leading scientists say the clinical trials and safety approvals needed to get a workable vaccine to market could take up to 18 months.

"The acceleration of this process is really truly dramatic in terms of what we're able to do, building on work that started with SARS, that started with MERS and now is being used for COVID-19 ," Dr. Maria Van Kerkhove, the technical lead for WHO's emergencies program, said at a press conference at the organization's headquarters in Geneva on Friday.

The World Health Organization is working with scientists across the globe on at least 20 different coronavirus vaccines with some already in clinical trials in record time — just 60 days after sequencing the gene.

Dr. Mike Ryan, executive director of WHO's emergencies program, said the trials are necessary. There's only one thing more dangerous than a bad virus "and that's a bad vaccine," he said.

"We have to be very, very, very careful in developing any product that we're going to inject into potentially most of the world's population," he said, adding that the first human trials on a vaccine that started this week in the U.S. were "unprecedented in speed." He said that would have never happened if China and other countries hadn't shared the genetic sequence of COVID-19 with the rest of the world.

The National Institutes of Health has been fast-tracking work with biotech company Moderna to develop a vaccine using the genetic sequence of the new coronavirus. The trial started Monday at the Kaiser Permanente Washington Health Research Institute in Seattle, Washington. 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.

Once a vaccine is found, WHO officials warned about other logistical, financial and ethical hurdles world leaders will face.

"Even if we get a vaccine that's effective, we have to have that vaccine that's available for everybody. There has to be fair and equitable access to that vaccine for everybody," Ryan said, adding the world won't be protected from the coronavirus unless everybody is vaccinated. "How do we ensure we get enough of that vaccine in time, how do we ensure, how do we ensure we can distribute that vaccine to populations all over the world and how do we convince people to take the vaccine."

WHO Director-General Tedros Adhanom Ghebreyesus has already been reaching out to global leaders on these issues, Ryan said.

"This vaccine should not be for the haves, it should be for those who cannot afford it too," Tedros said. "We need to answer that question as early as possible."

The virus has infected more than 245,000 people worldwide and killed at least 10,031, according to data compiled by Johns Hopkins University. U.S. cases have reached at least 14,250, with New York State comprising more than 40% of the nationwide total.

The outbreak started in Wuhan, China in December and has since spread rapidly around the world. The WHO announced last week that Europe has become the new epicenter of the outbreak.