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Do you need a Covid-19 booster shot? Seattle researchers aim to find out

caption: Doses of the Pfizer Covid-19 vaccine are shown ready to administer to students over the age of 12, on Tuesday, May 18, 2021, at Memorial Stadium in Seattle.
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Doses of the Pfizer Covid-19 vaccine are shown ready to administer to students over the age of 12, on Tuesday, May 18, 2021, at Memorial Stadium in Seattle.
KUOW Photo/Megan Farmer

When Jerome Miller got the chance to be part of the initial Covid-19 vaccine trials last summer, he jumped at the opportunity. But as the delta variant emerged across Washington and the United States, he started to wonder if he needed a booster shot.

Miller works with a vulnerable patient group at a Seattle hospital, helping with duties like scheduling surgeries and care. He rides public transit to work every day. He’s been terrified since the beginning of the pandemic that he’d get infected or even worse — pass the virus on to a patient.

"As hospital workers, we did not get to stay home like the rest of the world. So that was my main motivation in the beginning was, 'I don't want to kill one of my patients,'" Miller said.

For a long time after getting vaccinated, Miller was waiting for the rest of the world to catch up. Then, he started to wonder how long his immunity would hold.

"At the beginning of June that's when I started wondering, 'OK, I'm coming up on 10 months now, I think I should ask, are we going to get a booster? Do we need a booster?'"

Miller is not alone with this curiosity. As the Delta variant surges through Washington state, more people are wondering about the necessity of a Covid-19 vaccine booster shot — an extra dose to prolong immunity. Miller is now jumping back onto the research side to help find out.

Meanwhile, scientists, doctors, pharmaceutical companies and governments around the world continue to debate if, and when, boosters may be necessary. Answers may be found in Seattle, where researchers are testing various approaches to a booster shot.

A third dose?

Studies are underway to answer those very questions, with researchers in the Seattle area involved in exploring the role of booster shots.

When the trial for a third dose of the Pfizer-BioNTech vaccine began, Miller jumped at the chance to be involved once again.

"Where do I sign up? How quick? When can we make this happen?"

The purpose of the study is to find out whether boosters are necessary, safe and effective.

"We don't really know the answer to that yet,” said Dr. Sandra Lord, a principal investigator on the booster study funded by Pfizer, and the clinical director for the Center for Interventional Immunology at the Benaroya Research Institute at Virginia Mason.

The study is going on at multiple locations around the world. Half of the participants get a placebo, and half get a third dose of the Pfizer-BioNTech vaccine.

Lord and other scientists will monitor participants for a year via an app. They’ll also collect and analyze blood every couple of months to monitor their participants' immunity levels, any side effects, and infection rates.

It’s important for a number of reasons to answer these questions through studies, according to Lord.

"We don't have enough vaccines to go around and so we want to make sure that any vaccine that's administered is necessary. And then the other thing is that we don't know if a third vaccine is safe. It probably is, but that's the main caution that we need to remember," Lord said.

Lord thinks it's likely that a booster may be needed at some point. What remains unclear is the timeline. Could we need one a year after the initial shots? Two years? Five?

It’s likely that certain populations, like people who are older or immuno-compromised, might need them sooner.

But for now, Dr. Sandra Lord said she doesn't encourage people to seek out another dose on their own.

Tough decisions

Pfizer recently announced it will be seeking approval for booster shots to be authorized in the U.S. This was in part because of data from Israel that suggests reduced efficacy of the vaccine after about six months. However, that data hasn’t been peer reviewed yet, and scientists are still working to understand it.

The Centers for Disease Control and Prevention and the Food and Drug Administration have said that fully vaccinated people remain protected against the virus and don’t need boosters at this time.

Even though the studies are still underway, some wealthy countries have already authorized booster doses as the Delta variant drives yet another wave of infections.

However, these decisions have been controversial due to global access issues. Earlier this week, The World Health Organization called for a moratorium on booster shots until at least the end of September.

“I understand the concern of all governments to protect their people from the Delta variant. But we cannot accept countries that have already used most of the global supply of vaccines using even more of it, while the world’s most vulnerable people remain unprotected,” said WHO Director-General, Dr. Tedros Adhanom Ghebreyesus, in a briefing.

Seattle studies

The Pfizer study isn't the only one trying to answer questions about the role of booster shots in the fight against Covid. Another study at The University of Washington is looking at mixing and matching vaccines. For instance, giving someone who got the Johnson & Johnson shot a dose of Moderna.

The study is funded by the National Institutes of Health and going on at multiple sites across the country.

Dr. Tia Babu is an infectious diseases physician with UW Medicine and a sub-investigator on two booster studies.

She said mixing and matching vaccine platforms – mRNA shots with the Johnson & Johnson shot – could potentially stimulate the immune system in a different way.

“We will definitely be looking at that to see if there’s any chance that mixing different platforms of vaccine makes a difference in the immune response,” Babu said.

Babu said that study may also look at shots designed to target variants in the future.

The study is still enrolling individuals who had their final vaccine dose at least 12 weeks ago. Anyone interested in enrolling in the study can contact the UW virology research clinic at or 206-520-4212.

And an additional study will test a new vaccine as a booster to try to get a bigger overall immune response. If a Covid-19 vaccine booster is deemed necessary that wouldn’t be unusual.

Additional doses are required to create longer lasting immunity from many illnesses like measles, mumps, and tetanus. Yearly flu boosters also allow people to receive immunity against different strains of that virus.

“It’s not that the vaccines are not working,” Babu said.

Even with rare breakthrough cases, Babu said the vaccines provide significant protection from severe illness, hospitalization, and death.

“I don’t think we can emphasize enough how important it is to get vaccinated,” she said.

Babu said getting the initial shots to as many people as possible is what will curb the pandemic. If they end up being recommended, booster doses may just improve immune response.

At the Seattle Indian Health Board, Executive Vice President Abigail Echo-Hawk, a Pawnee Nation member, said they're watching the trials closely.

"The science is evolving and we have to expect that what we're being asked to do to prevent the spread of Covid-19 and to ensure the health and safety of all of us, it may evolve month-to-month,” Echo-Hawk said. "This is what good science looks like."

The Seattle Indian Health Board is putting a plan in place in case the science indicates boosters are necessary.

"We are making these emergency preparedness plans, we are prepping for what may come, and if it doesn't happen not a problem, we had a plan in place," Echo-Hawk said. "That has been the issue in this country is that we have not had the proper procedures in place for an emergency response, for vaccine rollout and for this pandemic."

She said the way the SIHB rolled out vaccines, focusing on who was most vulnerable and the people who served them, could be used as a model.

The initial vaccine rollout in Washington state revealed racial disparities, with lagging vaccination rates in Black and Hispanic communities.

Public health officials say partnering with community organizations has helped to begin closing the gaps and they would build on strategies that have worked if another rollout is needed.

Feeling great about feeling sick

After enrolling in the new Pfizer trial, Jerome Miller finally got his third shot on a recent Monday.

He spent the next day at home watching 70s re-runs of The Price is Right and feeling a little under the weather.

"I described it to one of my relatives who was checking on me as, 'well, it's like standing in a line at Disney Land outside in 100 degree weather for five hours. You know, I just feel tired, and achy, and hot,'" Miller said. "I was thrilled."

Miller knows that's a strange reaction to feeling sick, but he said he saw the reaction as an indication that he got the real deal, not the placebo shot.

He said potential side effects shouldn't scare people away from the vaccine or any potential boosters because the protection is worth it.

Miller is hoping this third shot will help him feel less anxious about everyday things, like taking the bus and going to work.

"It'll be so nice to just walk out my front door and not feel that anxiety," he said.

Regardless of whether booster shots become widely recommended or not, health and government officials say the most important thing to know is that the current vaccines work and anyone who is eligible and not yet vaccinated should get their shots.

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