Local Researcher Calls For Realistic Expectations For COVID-19 Vaccines

The hunt for a COVID-19 vaccine is in full force, with hundreds of vaccines in development and a handful already in clinical trials.

But a local immunologist, Dr. David Canaday with the Cleveland VA, published a paper calling for researchers to set more realistic expectations for a vaccine’s potential effectiveness.

Canaday said we shouldn’t expect perfection from any of the COVID vaccine candidates, and that their effectiveness will not be 100 percent.

"The range: 60 or 70 percent, or lower,” he said. “Once we get to some of these optimal vaccines that may take a bit more time, hopefully we'll get into the 90 percent range."

For older adults who already have more weakened immune systems, he said a vaccine’s effectiveness will likely be even worse. Because of this, Canaday said researchers should strive for a vaccine that not only protects someone from getting the virus – but helps mitigate the virus if they do end up getting it.

“The best type of vaccine will be a vaccine that’s kind of a balance,” he said. “It gets those antibodies that tries to protect you 100% in the first place, but then if it does break through that protection, then this vaccine also makes cells — called cell mediated immunity — to respond, and then that lessens the severity of the disease.”

Canaday also said while it’s likely most people have been exposed to other coronaviruses at some point in their life, current evidence suggests that this does not indicate they have any immunity to COVID-19. This will further affect the vaccine’s ability to prevent infection.

“That’s quite a bit different than flu, for example, where you have a baseline immunity, because we’ve all had flu or flu shots over our lifetime,” he said. “So you’re kind of like boosting things that are already there and just making them a bit better, whereas here, we’re starting from ground zero.”

He said it might be best to pursue combination vaccines, as was done for strep pneumonia.

“For strep pneumonia, you already have two different vaccines that work in different ways. To get optimal protection, you have to get both vaccines spread out over time. So we may be in a scenario where something like that would be optimal.”

Canaday co-authored the article with Dr. Stefan Gravenstein at Brown University. The paper was published Thursday in the peer-reviewed journal Clinical Infectious Diseases.