Answers to questions about COVID booster shots, mixing and matching

Confused? Health experts say regulators respond to data as it becomes available.

The staggered authorization in the U.S. of booster shots for three different brands of coronavirus vaccineshas been unwieldy and confusing.

Health experts explain this is just regulators responding to new data as it becomes available and this shouldn’t make us less confident in the shots’ benefits or safety.

“I’ve gotten the feedback, ‘You guys keep changing your minds and it’s confusing,’” said Dr. Roberto Colón, chief medical officer at Premier Health’s Miami Valley Hospital. “But it’s reacting to new data. It is modifying our recommendations based on what we are seeing. If we get new data that allows us to understand something better, and make a product or recommendation more effective and safer, we have a responsibility to respond to that and make the change.”

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Dr. Roberto Colón, chief medical officer at Miami Valley Hospital

Dr. Roberto Colón, chief medical officer at Miami Valley Hospital

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Dr. Roberto Colón, chief medical officer at Miami Valley Hospital

Readers continue to ask about the coronavirus pandemic, including many questions in recent weeks about vaccine boosters. So the Dayton Daily News assembled a panel of trusted local experts, including doctors and pharmacists, to provide answers on a regular basis.

Here is a guide on all things booster shots-related, how to decide which one to get and where to find them. If you have specific questions about your own situation, health experts recommend talking with your doctor or other primary care provider.

Q: What do boosters do for us?

A: Over time, coronavirus vaccines’ ability to prevent transmission has fallen, explained Zachary Jenkins, a clinical pharmacist with Premier Health and a professor of pharmacy practice at Cedarville University. But their ability to prevent severe illness and death has remained strong, he said. In 2021, unvaccinated Ohioans have made up 98% of statewide COVID-19 deaths, according to the Ohio Department of Health.

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Zach Jenkins, a clinical pharmacist with Premier Health and a professor of pharmacy practice at Cedarville University.

Zach Jenkins, a clinical pharmacist with Premier Health and a professor of pharmacy practice at Cedarville University.

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Zach Jenkins, a clinical pharmacist with Premier Health and a professor of pharmacy practice at Cedarville University.

“So probably the most benefit you’ll see from boosters initially is the decrease in overall rates of infection, and there will probably be a decrease in transmission,” Jenkins said. “So that’s, I think, kind of the initial target that they’re shooting for. And there’s a big debate we’re having in public policy and health care if that’s the goal we should shoot for, or it should be just shooting for preventing severe disease and infection.”

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Q: Who is eligible for a coronavirus vaccine booster and why?

A: Adults who received an mRNA vaccine (Moderna or Pfizer) are eligible for a booster if they received both shots at least six months ago and fall into one of the following categories set by the Centers for Disease Control and Prevention:

  • Anyone 65 and older.
  • Anyone 18 or older who lives or works in a long-term care facility, homeless shelter, prison or other congregate setting.
  • Front-line personnel 18 or older who are at a higher risk of COVID-19 exposure due to their job, including first responders, teachers, supermarket staff and mass transit employees.
  • All adults 18 to 64 who have a disease or condition that increases their likelihood of coronavirus complications, including: cancer, chronic kidney disease, chronic liver disease, chronic lung disease, dementia or other neurological conditions, diabetes, Down syndrome, heart conditions, HIV, mental health conditions, sickle cell disease or thalassemia; are immunocompromised, obese or overweight, a current or former smoker, a solid organ or blood stem cell transplant recipient.

Colón explained that the data was not overwhelmingly strong that people with high occupational exposure need a booster, but that group was added because they are crucial to keeping our society running.

All adult Johnson & Johnson recipients are now eligible for a booster dose if they received their first dose at least two months ago. Studies show protection from J&J vaccines, while good, has not been as strong as the two-dose mRNA vaccine series made by Moderna and Pfizer.

Q: Are booster doses the same as coronavirus vaccines given in the initial series?

A: Federal regulators approved Pfizer and J&J boosters that are the same as the shots given in the initial series. Moderna boosters are the same formula as their original counterpart but given at half the dose.

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Q: Am I allowed to mix and match shots from different manufacturers? And which is the best combination?

A: The Food and Drug Administration recently OK’d getting a booster shot of any of the three COVID-19 vaccines, even if it’s different from the one you initially received. This kind of mixing and matching has been used in Europe and other places, particularly when supply was low. Recent studies show this strategy is safe, effective and may even provide better protection.

Federal public health officials have declined to recommend one combination of vaccines over another.

“There is clearly some potential additional benefit from the mixing and matching, which is why that is being allowed,” Colón said. “We want to make clear there’s no evidence that there is extra risk from that crossover.” But he said the research doesn’t overwhelmingly point toward one vaccine combination being much better.

If you got Pfizer, preliminary research would suggest you get the Moderna vaccine to maximize your antibodies, but another Pfizer dose is likely similarly effective.

If you got Moderna, you got what seems to be the top-performing vaccine and switching manufacturers for your booster may not bring much benefit.

If you got J&J, you may want your second shot to be an mRNA vaccine (Moderna or Pfizer). The different kinds of shots stimulate different parts of the immune system, and some early research suggests it may be better for J&J recipients to get an mRNA booster.

“If you had J&J, get an mRNA vaccine,” Jenkins said. “I think the data is leaning pretty heavily in that direction. I couldn’t tell you which of those two is better. It sounds like Moderna is better on paper, but they also used twice the dose in that study than what we’re actually using right now.”

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Moderna boosters are only available in half doses, but a whole dose was used as a booster in the latest study of mixing and matching boosters. It’s also worth noting that the original dose of Moderna delivers more than three times as much active ingredient compared with Pfizer.

When selecting a booster, Jenkins and Colón recommends talking to your doctor or other primary care provider about your personal health conditions. You may want to consider how your body reacted to the initial series.

Or you may be concerned about different possible side effects (although all side effects are rare) from different vaccines. Males between 16 and 29 may have an increased risk of developing mild heart problems after receiving a Pfizer or Moderna vaccine. And the J&J vaccine has been linked to a small number of cases of blood clots in women between 18 and 50.

Q: If I had J&J, can I have a full Moderna dose?

“Nope,” Colón said. “The recommendation is a booster dose, which is a half dose of Moderna.”

If you’re going by the book, then no, you can’t get a full Moderna dose as a booster, Jenkins said.

“With that said, there were some members of the FDA’s advisory panel that questioned whether the half dose was actually going to be more problematic in the long term, as in, will it convert as much long-term protection,” Jenkins said. “It hasn’t been approved that way, but it’s not going to stop people from going and asking to get it like they’ve never received a vaccine before.”

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Q: I had my initial series of coronavirus vaccines, then I got COVID-19. Do I still need a booster?

While a common question, this is a special case that’s not addressed in any public health recommendations, Colón said.

“What we do know is people who are in that category of having been previously infected then vaccinated appear to have a higher degree of immunity of protection,” he said. “There is not a carve out for people that have been previously infected to say you should or shouldn’t. So in the absence of that, it would still be something that would be recommended for people who have had breakthrough infection after completing the series that they go ahead and get a booster. The importance of that may not be as great as for other people.”

Jenkins said this is where medical nuance and public policy butt heads.

“If somebody has been actually infected, the data would suggest that probably one shot or two shots is enough,” he said. “Honestly, I am of the opinion that a single shot in someone that’s been naturally infected, especially if it’s been recent, that’s probably all that they need.”

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Q: Will we have to get a booster every year?

Colón said it’s too early to predict how often we may need boosters.

“I would love to say no, and that we’re going to be done with COVID, but we just don’t know,” he said. “We don’t know if this is going to be an ongoing requirement and if it is, for how long? Or if this will just become an endemic type of virus that doesn’t require any additional immunization.”

Q: If I’m immunocompromised, how many doses can I get?

If you have a weakened immune system and you received the Moderna or Pfizer vaccines, U.S. health authorities recommend you get a third dose as part of the initial series four weeks after your second dose. That means you also qualify for a booster shot six months after your third dose.

Q: I’m one of the people not eligible for a booster right now. Should I be concerned I’m not adequately protected?

“I would not be very concerned about that,” Jenkins said. “If that person is really individually interested in pursuing a booster shot, that’s a conversation I would have with my physician … I would say more than likely, they’re going to be protected against the most severe parts of illness. I wouldn’t really proceed with too much concern.”

Colón explained that young, healthy adults are still well protected.

“So right now if you happen to be one of those individuals who does not meet the indication for the booster, sit tight,” he said. “Take the extra precautions and make sure to wear a mask. But realize you’re not losing your protection. The vaccine booster right now may just not be as important for you as it may be for some of these higher risk individuals.”

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Q: Where can I get a booster shot?

Note that coronavirus vaccines are free for all U.S. residents whether or not you have insurance.

Here are some of the local providers administering booster shots. Not all locations have all three vaccine brands. All of these providers also offer first and second doses, and third doses for immunocompromised individuals. More providers can also be found at

Premier Health is offering Pfizer booster shots at clinics around the Dayton area. To make an appointment, go to or call 937-276-4141 seven days a week.

Kettering Health is offering the Pfizer booster shots at a clinic in Kettering. Make an appointment online at or call 844-576-3627.

Five Rivers Health Centers is offering Pfizer and Moderna booster shots. Call 937-503-5664 to make an appointment or walk in in from 8 a.m. to 4 p.m. at one of two locations:

  • Family Health Center, 2261 Philadelphia Dr., Dayton
  • Medical Surgical Health Center, 725 S. Ludlow St., Dayton

CVS Pharmacy: visit or call your local pharmacy.

Kroger Pharmacy: visit or call 866-211-5320.

Meijer Pharmacy: visit, text COVID to 75049 or call your local pharmacy.

Rite Aid Pharmacy: visit

Walgreens Pharmacy: visit

Walmart Pharmacy: visit

Butler County General Health District is offering all three brands of boosters at its clinics held from 9 a.m. to noon at the Butler County Educational Service Center, 400 N. Erie Blvd., Suite A, Hamilton. Find clinic dates and register for an appointment at Pre-registration is preferred, but walk-ins are welcome.

The Clark County Combined Health District COVID-19 Vaccination Center at 110 W. Leffel Lane in Springfield is open from 9 a.m. to 5 p.m. Monday, Wednesday and Friday; and from 1 to 7 p.m. on Tuesday and Thursday. Call 937-717-2439 to schedule an appointment.

Champaign Health District is offering the COVID-19 vaccines on select days at 1512 S. U.S. Route 68, Suite Q-100, Urbana. Register online at or call the department at 937-484-1605.

Public Health-Dayton & Montgomery County is offering Pfizer, Moderna and J&J booster doses at its clinics. Find more information and schedule an appointment online at or call 937-225-6217.

Greene County Public Health is offering Pfizer, Moderna and J&J booster doses Tuesday, Thursday and Friday 8:30 to 11:30 a.m. and 1:30 to 3:30 p.m. at the main office at 360 Wilson Drive, Xenia. You can schedule an appointment at

Miami County Public Health is offering booster shots by appointment at the health department at 510 W Water St., #130, Troy. To make an appointment call 937-573-3500.

Warren County Health District is offering Pfizer and Moderna booster shots at the health department at 416 S. East St., Lebanon. Call 513-695-1229 for an appointment.

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