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An Iowa pharmacist answers your questions about COVID-19 boosters

Pat Moore, with the Chester County, Pa., Health Department, fills out a vaccination record card before administering the Moderna COVID-19 vaccine to emergency medical workers and healthcare personnel at the Chester County Government Services Center, Tuesday, Dec. 29, 2020, in West Chester, Pa. (AP Photo/Matt Slocum)
Matt Slocum/AP
Booster vaccines can prevent severe cases of COVID-19 and prevent hospitalizations at a time when healthcare systems are already overwhelmed.

In Iowa, hospitalizations and the state’s coronavirus test positivity rate are increasing once again.

According to state data, 68.5 percent of Iowans age 18 and older are fully vaccinated. Many of these Iowans are now eligible for COVID-19 booster vaccines. If you're over the age of 65, have a health condition that puts you at risk for complications, or work in a job that puts you at greater risk of contracting the disease, you're eligible. If you got the Johnson & Johnson vaccine, you're also eligible for a booster. Booster shots may be available to more Americans soon.

Most experts agree that immunizing unvaccinated people will more effectively stop the spread of COVID-19 than providing booster doses to those who are already vaccinated. But booster shots can prevent severe cases of COVID-19 and prevent hospitalizations at a time when healthcare systems are already overwhelmed.

“We believe that the booster will give our immune system that kick that it needs to remember what it's supposed to do,” says Mike Brownlee, associate director and chief pharmacy officer of the University of Iowa Hospitals & Clinics.

But all of this does raise a lot of questions for people. A common one, says Brownlee, is whether the need for a booster means the vaccine is not working.

In short, the answer is no.

“What we talk about in terms of vaccine efficacy is that it has declined slightly over time, primarily in preventing symptomatic disease, more mild to moderate,” says Brownlee. “So over time, we've seen that with other vaccines, too, that they do require boosters or additional doses, and that's not uncommon. The vaccines do continue to be very effective, but this boost will get us back up to that higher level of 95 percent of preventing not just the serious complications, but some of those more mild to moderate as well.”

That higher level of prevention can help reduce the risk of spreading the virus, as well. “When you're more acutely ill or sick, you have high risk, higher volume of virus in your body, and you can more easily transmit. The data are still emerging related to how much transmission is actually made if you are vaccinated. But the more that we can keep from being ill from the virus, the less spread we're going to have.”

Still, some people are hesitant to get a booster shot when there are people around the world who want an initial vaccine and have been unable to get one. But booster shots in the United States do not appear to be a factor in making vaccines available in other countries.

What kind of booster should I get?

When vaccines rolled out initially, health officials advised Americans to get whichever vaccine was readily available to them. Individuals seeking booster shots may have more options.

Those who initially received the one-dose Johnson & Johnson vaccine are eligible for a booster shot, and some doctors recommend boosters for J&J recipients as soon as possible. Those individuals have options about which vaccine booster they get. The Food and Drug Administration and Centers for Disease Control have authorized a mix-and-match approach to vaccines, and some limited, initial research has suggested that a booster dose of an mRNA vaccine may be more effective at preventing COVID-19, although Brownlees says a booster dose of the Johnson & Johnson vaccine still strengthens protection.

“Receiving Johnson & Johnson for one dose definitely did not maintain effect as long as the two doses for mRNA-based (the Pfizer and Moderna vaccines are both mRNA-based),” says Brownlee. “But getting that second dose of Johnson & Johnson does give you very good protection.”

Individuals may also consider how initial doses of the vaccine affected them. For example, if someone had a strong reaction to the Moderna vaccine, they may ask for a Pfizer booster in order to lessen the side effects. “The other thing to remember about the Moderna booster is it's half of the dose of the full course. So the side effects might actually be less. Or you could cross over and receive the Pfizer booster as well and potentially anticipate less side effects from that. So you got some options to think about when looking at the booster.”

In addition, young men are at a higher risk of rare, temporary inflammation in parts of the heart after receiving an mRNA vaccine and young women are at higher risk for thrombosis with thrombocytopenia syndrome after receiving the Johnson & Johnson vaccine (in the U.S., there are under 50 reported cases, overall, out of the 15 million people who've received the J&J vaccine). Brownlee encourages people to ask their doctors and pharmacists for their recommendations and to research some FAQs using reliable sources like the CDCand UIHC websites. You can also take this quiz from the NPR Shots team as a starting point.

I contracted a breakthrough infection. Can I get a booster?

Yes, says Brownlee.

“The only waiting period you have is really until the COVID has resolved and you're out of your isolation period. So you've got 10 days after symptom onset for isolation to be over, and then you're eligible to receive the vaccine. There's really no lengthy waiting period at all.”

How long will the protection last?

Doctors and researchers say that while the protection provided by the mRNA vaccines is waning slightly, that doesn’t mean they aren’t working. The most notable declines are related to the vaccine's ability to stop asymptomatic or mild breakthrough infections. They’re still incredibly effective at preventing severe cases requiring hospitalization (and that require scarce hospital resources) and death.

But how long will the added protection of a booster last? It’s too early to tell. “We're not sure exactly how long the booster is going to last because we need more time to evaluate that at this time.”

That said, influenza vaccines are offered seasonally because the virus evolves quickly. And the CDC has long recommended regular boosters for Td or Tdap vaccines.

Is it too late to get a first dose of the vaccine?

No, you can still get vaccinated, and getting a booster should not prevent someone else from getting an initial vaccination.

“We still continue to see a large number of patients coming in for their first doses, in addition to providing boosters,” Brownlee says. “There's a lot of energy, especially now with kids being able to be eligible for the vaccine, that there's more talk about it in the community and we still continue to see those receiving the first dose."

Brownlee made his comments on Talk of Iowa.

Corrected: November 17, 2021 at 1:32 PM CST
Mike Brownlee is the associate director and chief pharmacy officer of the University of Iowa Hospitals & Clinics. A previous version of this post erroneously stated that Brownlee is a doctor. We apologize for the error.

Caitlin Troutman is a talk show producer at Iowa Public Radio
Charity Nebbe is the host of IPR's Talk of Iowa
Matthew was a producer for IPR's River to River and Talk of Iowa