By Kathleen Berger, Executive Producer for Science and Technology

The delta variant caused a surge of infections. But research at Washington University School of Medicine in St. Louis shows how COVID-19 vaccinations offer protection, which helps to explain why vaccine booster shots are encouraged.

“Vaccines train your body to make antibodies against some of the emerging variants such as beta and delta because your body is very good at making lots of different antibodies against many different parts of the virus,” said Jacco Boon, PhD, associate professor of medicine, of molecular microbiology and of pathology & immunology. “And as long as there is a part of the virus that is conserve, in other words it has not changed much, you’re immune system, your defense system, will find it and will start to target it.”

Dr. Boon is co-corresponding author of the research analyzing antibodies produced in response to the Pfizer COVID-19 vaccine. Through laboratory testing, the research team discovered that the delta variant was unable to evade all but one of the antibodies.

“It’s a particular protein or antibody we call it to 2C08,” he explained. “Not only did we found in people that were vaccinated, we also found it in people that were previously infected with SARS-CoV-2. So this means that the vaccine can train your body in the same way a natural infection does.”

The expectation is that all COVID-19 vaccines generate the same 2C08 antibody.

“The unique thing about this antibody is that not only was it very potent, but it also recognized that part of the virus that so far hasn’t changed yet. So that means that the vaccine, even though it was made with the original virus with the spike protein of the original virus, it still induces protection against emerging variants,” Boon said. “We hope that the antibody will continue to provide protection against even future emerging variants, and we will continue to monitor that as well.”

Boon said the research helps explain why vaccinated people largely escaped the delta surge.

“It is a very efficient and very potent antibody. You only need a little bit of it to block the virus from infecting cells in the lab.”

While both natural infection and vaccination provide the antibody protection, just how long it lasts needs investigation. This is why Boon recommends booster shots.

“There’s a phenomenon called waning. So even though immediately after infection, you have a lot of antibodies in your body, overtime they go away. And so that is one of the reasons why we need to get boosters,” he said. “We don’t know how often. Will it be like the influenza vaccine, which we have to get every year? Or will it be like a different vaccine, such as Hepatitis B, or some other vaccine where we have to get it every 10 years? We don’t know yet.”