As the coronavirus pandemic continues to sweep the globe, hundreds of medical experts have teamed up in the hopes of creating a vaccine that will work against the deadly virus. But what if none of them succeeds?

Experts are confident that a COVID-19 vaccine will eventually be developed because unlike HIV and malaria, the novel coronavirus does not mutate rapidly. However, their optimism doesn’t take away the possibility that no vaccine may ever be developed at all. It has happened before, it can happen again.

According to Dr. David Nabarro, a professor of Global Health at Imperial College London, there is no assurance that a coronavirus vaccine will ever be developed. “There are some viruses that we still do not have vaccines against,” he said. “We can’t make an absolute assumption that a vaccine will appear at all, or if it does appear, whether it will pass all the tests of efficacy and safety,” he added.

If experts fail to develop a coronavirus vaccine, then COVID-19 will continue to spread, leaving societies with no other choice but to live with it. People will adjust to the new normal as cities open and return some of their old freedoms upon the recommendation of experts.

Testing and physical tracing will also become a normal part of everyday life, though a sudden instruction to self-isolate may be ordered in hard-hit countries. While experts may eventually develop a treatment for the disease, a lack of vaccine that will protect people from the virus means outbreaks of COVID-19 will continue to occur each year, causing the global coronavirus death toll to continue ticking upwards.

The timetable for the development of a vaccine is 18 months. If a coronavirus vaccine remains unavailable next year, then people will have to continue on with their lives with the constant threat of a disease they are incapable of stamping out.

“It’s absolutely essential that all societies everywhere get themselves into a position where they are able to defend against the coronavirus as a constant threat and to be able to go about social life and economic activity with the virus in our midst,” said Nabarro.

Coronavirus COVID-19 Laboratory Test, Cure, Vaccine Andressa Parreiras, Biomedic, and Larissa Vuitika, biologist, work in a laboratory during the extraction of the virus genetic material on March 24, 2020 in Belo Horizonte, Brazil. The Ministry of Health convened The Technological Vaccine Center of the Federal University of Minas Gerais laboratory to conduct research on the coronavirus (COVID-19) in order to diagnose, test and develop a vaccine. According to the Ministry of Health, as of Tuesday, March 24, Brazil has 1.891 confirmed cases of the coronavirus (COVID-19) and at least 34 recorded deceases. Pedro Vilela/Getty Images