(CNN) - From Tokyo to Quebec, from Iowa to New Orleans to Australia, scientists are in a race to come up with a vaccine to end the scourge of COVID-19.
There are more than 80 vaccine developers in all, according to the World Health Organization.
A vaccine group even suggested that the vaccines be manufactured before they’ve been fully tested. So far, seven are in human trials.
On March 16, a study volunteer was vaccinated in Seattle as part of a trial sponsored by the National Institutes of Health. Two other vaccine companies followed, one Chinese and one American.
"We're dealing with an unprecedented global health problem," said Dr. Anthony Fauci, head of the National Institutes of Allergies and Infectious Diseases with the NIH. "If we don't get control of it, we will never get back to normal."
Researchers at Oxford University in England vaccinated their first patient April 23.
"What we’re doing with any vaccine is trying to trick the immune system into thinking that there’s a serious infection here that the immune system needs to respond to," said Sara Gilbert, with Oxford University.
Different vaccines work in different ways, Fauci said.
“We’re using everything from genetic immunization with RNA and DNA vaccines, viral vectors, live attenuated proteins, nanoparticles, etcetera,” he said.
That’s a good thing, said Dr. Peter Hotez, a vaccine expert at Baylor College of Medicine in Houston.
"By having that diverse array of different technologies, it increases the likelihood that you’ll get one or two or three that will reach the finish line," Hotez said.
Most of the vaccines likely won't work, and those that do will take a long time to be tested.
"Dr. Fauci has charged us with doing this in a year to 18 month. That would be a world record, and we’re trying our best," Hotez said.
Hotez, who also is working on a vaccine, thinks it will take significantly longer than that to complete human trials. Researchers spend many months giving vaccines to their human study subjects to make sure they’re safe and effective.
With dozens of companies developing vaccines, it’s possible some might be overly optimistic.
"You may think they’re talking to the general public, but what they’re really doing is talking to their shareholders and investors, so try to stay calm," Hotez said. "You want to be able to kind of distance yourself from a lot of the hype."