covid booster shot

Should J&J Recipients Get an mRNA Booster? Chicago's Top Doc Explains

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Mixing and matching refers to giving a booster dose of a vaccine that’s different from the vaccine type that was used for the initial vaccination series. Here’s what we know so far.

Which COVID vaccine booster should you get based on your initial vaccination?

Chicago's top doctor, Dr. Allison Arwady, broke down Tuesday the best options.

Arwady said that while the first doses of the vaccine remain the most important, choosing your booster dose can also be an important decision.

The FDA opened the way for anyone eligible for a booster to get any of the country's three authorized brands for their extra dose. The FDA stressed the practicality of being able to get whatever booster a particular pharmacy or clinic is offering, particularly in nursing homes and other institutional settings where residents have received different shots over time.

CDC advisors also endorsed “mixing and matching” brands for the extra dose -- a key step in the federal push to broaden booster access for the U.S. public.

But neither agency gave recommendations surrounding combinations of vaccines and booster doses.

So how can you choose?

Here's what Arwady had to say:

If you got Johnson & Johnson for your first dose:

For those who received the Johnson & Johnson vaccine, Arwady said "we definitely are seeing people choosing to get the Pfizer or Moderna as their follow up dose," a move she "fully supports."

"If you got Johnson and Johnson, I have been advising folks if they got J&J, depending on the reason they chose J&J the first time, if they're going to get that booster I've been recommending getting likely one of the mRNA series - the Moderna or the Pfizer," she said. "That's where we saw the biggest increase in antibodies in the studies."

She noted, however, that "getting that second dose of J&J also majorly increases the protection."

If you got Moderna or Pfizer for your first dose:

Federal regulators have recommended getting the same shot as your first dose for booster doses, and Arwady said that applies particularly to those who got an mRNA vaccine.

"If you got Moderna or Pfizer, I would recommend sticking with the same one that you got initially," she said.

Doses of the two vaccine makers' booster shots are different.

Moderna's booster dose will be half of its original dosing, while Pfizer's booster shot is the same as the initial doses.

Still unsure which brand you should to get?

The decision to allow "mixing and matching" for booster doses comes after a highly anticipated study found the approach to be safe and effective, though the Moderna and Pfizer-BioNTech vaccines were found to spark a stronger immune system response than Johnson & Johnson.

The National Institutes of Health study, which was released earlier this month and has yet to be peer reviewed, found that people who received the Johnson & Johnson vaccine produced stronger antibody levels after receiving a booster shot made by Moderna or Pfizer, compared to a booster from Johnson & Johnson. Those who were originally vaccinated with the Pfizer or Moderna vaccines and received either company's booster shot produced comparably strong immune responses, the researchers observed.

For a complete breakdown of who is eligible for a COVID vaccine booster shot, click here.

NBC Chicago/Associated Press