COVID-19 vaccine boosters: What’s the difference

KELOLAND.com Original

SIOUX FALLS, S.D. (KELO) — A FDA panel on Thursday set in motion the road to Moderna COVID-19 vaccine booster shots, endorsing a lower-dose booster for seniors, as well as younger adults with other health problems, jobs or living situations that put them at increased risk from COVID-19.

This endorsement was also given Friday to the Johnson and Johnson vaccine, which the FDA is recommending for anyone age 18 and up who received their first dose at least two months ago.

These endorsements must still pass FDA leadership and the CDC before Moderna and J&J boosters can be given out, but if both agencies approve, boosters could begin as soon as this month.

The purpose of a booster shot of the COVID-19 vaccine is to ‘boost’ the production of antibodies to the virus in your body. According to Avera’s Dr. David Basel, your body still remembers how to produce the COVID-19 antibodies if you’ve already been vaccinated, but will require a booster to tell it to continue producing them.

The booster is saying, ‘This is not a one-time infection you’re going to see. You may see this again and again in the future, so keep making those antibodies.’

Dr. David Basel

The Pfizer vaccine booster was granted approval in September and those who get it will received a full dose. The Moderna booster, if approved, will be given in a lower dose. KELOLAND News spoke to Basel, as well as Sanford Health Dr. Jeremy Cauwels to find out why.

“The booster that [the FDA] approved was essentially half the original dose of the original Moderna series,” said Basel. “With Moderna, the first and second shot are half a cc — half a milliliter. For the booster, it’s going to be a quarter of a milliliter.”

Basel says this reduction in the volume of vaccine was the result of a study showing a lower dose is all that is needed to boost antibody production up to adequate levels.

Another positive effect of this discovery is highlighted by Cauwels.

“When they give that additional dose, less of the medicine is actually needed to induce the same sort of covering immune response,” he said. “As you can imagine, as we’re trying to distribute doses throughout the world.”

The less dose we can give to each individual means the more doses we can spread out to the world.

Dr. Jeremey Cauwels

Basel stressed the fact that even though the Moderna vaccine will be a lower dose, it is still the same vaccine.

“The booster’s the exact same formulation as the initial series. It’s just half the vaccine,” Basel said.

Asked why the Pfizer vaccine isn’t a lower dose, Basel points to timing.

“They probably could have studied at a lower dose for that third shot, and it likely would have been okay knowing what we know now — it’s just not how they set it up,” Basel said.

Basel says that because the authorization for Pfizer boosters came about a month ahead of the others, Moderna may have been able to benefit from what was already known to determine that it could use a lower dose.

Cauwels said that while the current Pfizer booster is a full dose, studies may change that in the future.

“For instance, the Pfizer dose in children is a lower dose because children do a better job of forming an immune response,” Cauwels said.

When addressing the need for a booster shot, Basel outlined the difference between a primary dose and a booster.

“There’s the primary dose series where you’re getting one, two or even three shots of a vaccine to get your initial immune response up to a level that it’s going to be effective,” he said. “That’s your primary series.”

“Over time,” Basel continued “after that primary series [immunity] drops off and you need a booster.”

Basel said some people like those who are immunocompromised do not mount as strong of an immune response to the first shots and may require an additional one in series to reach full initial immunity.

Copyright 2021 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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