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COVID Booster Shots: When Are They Needed? Are They Effective Against The Delta Variant?

NEW YORK (CBSNewYork) -- The U.S. vaccination rate continues to slowly improve, recently climbing past 60% of the eligible population, but now questions and confusion have arisen over booster shots.

CBS2's Dr. Max Gomez has some answers about if and when we need them and if they're effective against the Delta variant.

Based on how long immunity lasts to other coronavirus vaccines, vaccine experts have presumed that we would eventually need booster shots to maintain effective immunity to the constantly developing variants of COVID-19, not unlike needing a flu shot every year because influenza virus rapidly mutates.


Here's what we know so far.

Federal regulators are considering approving a COVID-19 booster shot starting as soon as five months after the previous dose.

It's not clear why five months rather than the eight-month gap previously announced other than they expect to have ample vaccine supply by then and new data from Israel indicate a booster dose provided four times as much protection against the Delta variant than the previous two-dose regimen in people 60 and older.

The booster dose also provided five to six times more efficacy in preventing hospitalization or serious illness.

The Food and Drug Administration granted full approval of the Pfizer vaccine this week. Moderna's full approval application is expected within three months, and Johnson & Johnson has said it will apply for full approval later this year.

Those booster shots are initially expected to be identical formulations as the first shots.

As for effectiveness with a third booster dose, Pfizer has reported that the level of neutralizing antibodies after that booster was more than three times that generated after their two-dose regimen, and those higher levels provided significantly greater protection against the original virus, as well as the Beta and Delta variants.

A similar enhancement in immunity is expected with the virtually identical Moderna vaccine. On Wednesday, Johnson & Johnson said a second dose of its vaccine also generated a stronger immune response, justifying a booster shot of their vaccine as well. Again, these are the same formulas as the first shots.

Because mixing and matching vaccine brands has not been studied, approval for that strategy is unlikely for now, especially for getting a Moderna or Pfizer booster after a Johnson & Johnson shot.

Booster shots have been approved for people age 65 and older and people with compromised immune systems. More tweaks to these approvals are expected as the FDA evaluates data submitted by manufacturers.


Additionally, primary care physician Dr. Amy Crawford-Faucher, with the Allegheny Health Network, says people can now get their flu shot and COVID booster around the same time.

Until a few months ago, scientists didn't want the two vaccines to overlap.

"Because we were just rolling this out to lots of people, we really wanted to be pure in knowing that if you had a reaction, it was due to the COVID vaccine and not from something else," Crawford-Faucher said.

Experts warn against skipping the flu shot, saying it's not likely that we'll see another winter with low flu cases.

"We were working from home. We were doing school from home. We were limiting the number of contacts that we had, and we were all masking. Obviously, that has changed and will probably remain changed going into this winter," said Dr. Graham Snyder, with the University of Pittsburgh Medical Center.

Doctors advise scheduling both shots in whatever order works best for your schedule.

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