Global public health officials are warning that the coronavirus circulating around the world right now will take years to completely contain and that the virus might never totally go away.

"I would say in a four- to five-year time frame, we could be looking at controlling this," Soumya Swaminathan, the World Health Organization's (WHO) chief scientist, told a Financial Times conference on Wednesday. Swaminathan warned that the current pandemic could "potentially get worse" before it gets better.

At a press conference later on Wednesday, another senior WHO official said the coronavirus — known by its scientific name SARS-CoV2 — might never be completely eradicated.

"We have a new virus entering the human pop for the first time, and therefore it is very hard to predict when we will prevail over it," said Mike Ryan, director of the WHO's emergency program. "This virus may become just another endemic virus in our communities. This virus may never go away. HIV has never gone away."

"It is important that we be realistic, and I don't think anyone can predict whether this virus will disappear," Ryan said.

The comments come even as some scientists working on a vaccine are moving toward human trials on an expedited time frame. Ending the coronavirus as a threat to humanity is more complicated than simply developing a vaccine, experts said, because that vaccine must be developed and distributed on a mass scale in order to stamp out the virus.

But even some viruses for which vaccines are available are never completely stamped out. Diseases like measles, tuberculosis and the seasonal flu all have vaccines, but either they are not universally available or they are not completely effective.

"We have many candidates and hope to have multiple winners. In other words, it’s multiple shots on goal," Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, told the Senate Health, Education, Labor and Pensions Committee on Tuesday.

"I must warn that there’s also the possibility of negative consequences where certain vaccines can actually enhance the negative effect of the infection. The big unknown is efficacy. Will it be present or absent and how durable will it be?"

In January, Fauci predicted that a new vaccine for the coronavirus might be developed in a span of 12 to 18 months. That timeline is ambitious; the previous record for the fastest vaccine produced in the face of a new virus is four years, the time it took to develop a vaccine for the mumps.

Even if a vaccine is developed and clears the tremendous hurdles in proving it is both safe and effective, it will take months more to produce it on a vast scale. Billions of doses must be both produced and distributed in order to halt the virus in its tracks.