DETROIT – Efforts to find a coronavirus (COVID-19) vaccine are about to take another major step forward, though declining cases could actually hamper those efforts.
In order to know if a vaccine is actually protecting the people who have been vaccinated, those people need to be exposed to the virus. Researchers can’t deliberately expose participants to the coronavirus in clinical trials, so the virus needs to be circulating in the community.
That means the success of the trials will come down to location.
“If you go in and you have dribs and drabs of infection, even though you have 30,000 people in the combination of placebo and experimental, it could take months and months and months to get an answer,” Dr. Anthony Fauci said.
Speaking to the Journal of the American Medical Association, Fauci said next month, sites are now being prepared to start large phase three studies of the Moderna vaccine developed at the National Institutes of Health.
It’s critical to test the vaccine where the virus is spreading.
“It you start to phase three, and then when you’re a month or two into it you happen to get in an area that you highly vaccinated where you’ve had a big outburst of a surge of cases, you could get your answer pretty quickly,” Fauci said.
Those trials will be located in the United States and other countries.
Starting this month, Brazil will host the next round of testing on the COVID-19 vaccine being developed by Oxford University and AstraZeneca. Brazil has the second highest number of cases after the U.S., and the curve there is still rising.
Fauci said he remains cautiously optimistic that an effective vaccine can be made.
“The majority of people make an immune response which clears the virus, which tells us that if the body is capable of making an immune response to clear the virus of natural infection -- that’s a pretty good proof of concept to say that you’re going to make an immune response in response to a vaccine,” Fauci said.
Fauci said he is concerned about the durability of that immune response, meaning how long it will last. With several other coronavirus strands, such as those that cause the common cold, the length of protection is generally a year or less.
We still don’t know how long any protection -- from recovering or from a vaccine -- might ultimately last.
The vaccines will be tested primarily in people ages 18 to 55, but there will also be elderly volunteers, as well as people with underlying health issues.
The phase three trial is designed to get a much bigger picture of how people respond to the vaccine and any potential side effects, so they are casting a wider net on participants.