Finding how much protection is enough when it comes to COVID-19 vaccines

At Fred Hutch in Seattle, Dr. Peter Gilbert is working to find out how much of an immune response is enough to protect you from COVID-19. The measurement he is working to find is the “correlate of protection,” a measurement of the antibodies in the blood.

Gilbert is a biostatistician who spent 20 years working on a vaccine for HIV. When the pandemic hit, he quickly shifted to work on COVID-19.

“We learned expertise so that when the SARS-2 virus came along, we were ready to pivot and transfer that expertise to COVID,” said Gilbert.

Gilbert is studying how much of an immune response is enough when it comes to COVID-19 vaccines. He’s looking at the antibody markers in the blood of people who have been vaccinated. His team analyzes the data from the phase 3 clinical trials overseen by Fred Hutch, as part of Operation Warp Speed.

“We measure the concentration of the antibodies in the blood that we find in the sample in someone that got vaccinated,” said Gilbert.

The hope is it will reveal how well these vaccines protect people with other health issues.

“That will help us make decisions about approving vaccines for different sub-populations, like cancer patients,” he said.

It will also help determine when to offer COVID-19 booster shots.

The research is being watched closely by other doctors developing COVID-19 vaccines, including Dr. Deborah Fuller at UW Medicine.

“His work is so important for a number of reasons. One, understanding what is the threshold because we’re obviously seeing immune responses wane. But then, when do we need a boost?” said Fuller, UW Medicine.

Finding out how much of an immune response is enough and assigning it a number can be effective when it comes to targeting the variants too, according to Gilbert.

“We’d love to be able to predict efficacy based on a blood marker because then you can do a small fast study, a cost-effective study and some answers and get some vaccines approved as quickly as possible,” said Gilbert.

He said it could allow researchers to test vaccines on hundreds of people instead of thousands, which could speed up the process of creating new vaccines.