The COVID-19 vaccines from Pfizer and Moderna produce a "persistent" immune response and give a sign of long-lasting protection, a new study finds.
The study is a positive development in the discussion around whether booster shots of the vaccines will be needed and when, though there has not been a definitive answer to that question yet.
The study published in the journal Nature on Monday centers on what are known as germinal centers, what Ali Ellebedy, the study's senior author and an associate professor at Washington University in St. Louis, describes as "boot camps for immune cells."
The study found that those training grounds in the body for immune cells were still active 15 weeks after the first dose of vaccine.
“Germinal centers are the key to a persistent, protective immune response,” Ellebedy said in a statement. “Germinal centers are where our immune memories are formed. And the longer we have a germinal center, the stronger and more durable our immunity will be because there’s a fierce selection process happening there, and only the best immune cells survive."
"We found that germinal centers were still going strong 15 weeks after the vaccine’s first dose," he added. "We’re still monitoring the germinal centers, and they’re not declining; in some people, they’re still ongoing. This is truly remarkable.”
One key wild card in the discussion of booster doses is what variants of the virus develop. So far, the vaccines have held up well against new variants of the virus, including the highly transmissible delta variant that is on the rise in the United States.
But if a new variant develops that is more resistant to the current vaccines, that could prompt a need for booster doses, possibly with a modified vaccine designed to fight the new variant.