One of the country's top vaccine experts has stirred debate in recent weeks by suggesting that not everyone should get the latest COVID-19 vaccine boosters and that the CDC is "overselling" the new shot.

Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia and a member of the FDA's committee of outside vaccine experts, told Yahoo Finance there are three main groups of people who will benefit the most from the bivalent booster based on current evidence — those who are older than 75, have chronic diseases, or are immunocompromised.

For healthier, younger individuals, the vaccine's impact isn't as strong, he said.

"I just don't think it's going to make much of an impact in otherwise healthy young people. We really should focus on those three groups who are most likely to benefit, because the goal of the vaccine is to protect against serious illness. It's the only reasonable goal, it's the only attainable goal," he said.

The clinical results of the first COVID-19 vaccines in 2020 had surprised experts with strong protection against mild illness, but subsequent variants eroded that level of protection over time. However protection against severe illness and death remains strong — and that should remain the focal point, Offit said.

He noted that some reports about his comments have misconstrued his claim to suggest that younger individuals shouldn't get the booster. He stressed instead that it's a matter of "low risk, low reward."

"We're not going to be able to stop mild illness, we're not going to be able to stop transmission, and to try and do that with frequent boosters ... doesn't make a lot of sense," Offit said.

That's because boosters only buy a few extra months of protection against mild illness before the antibodies wane, he said, and studies have shown that the vaccines do not necessarily prevent transmission.