Study finds Pfizer, Moderna vaccine immunity lasts longer. Do we still need booster shots?

Both the Pfizer-BioNTech and Moderna COVID-19 vaccines have set off an immune system response that likely offers longer-lasting protection against the coronavirus, according to a new study released on Monday.

The findings, which were published in the journal Nature, add more evidence to the notion that people immunized with mRNA vaccines may need less or even no boosters at all after they’ve been given their two shots.

According to the study, such mRNA-based vaccines create a more “persistent” germinal centre B cell response, essentially meaning that a person’s immune response would be much stronger and more durable.

“Germinal centers are the key to a persistent, protective immune response,” said senior author of the study, Dr. Ali Ellebedy in a press release.

Ellebedy, who is also an associate professor at the Washington University School of Medicine, said such centres are where “our immune memories” are formed and that the longer we have them, the more durable our immunity would be due to a “fierce selection process” happening there.

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While both Pfizer and Moderna have previously said that booster shots would likely be needed on an annual basis, the results come amid mounting evidence of the mRNA vaccines’ efficacy, and longevity, of protecting against COVID-19 — without the need of a booster.

The researchers examined participants four months after they received their first Pfizer dose and found that the germinal centres in their lymph nodes, likened to a sort of boot camp for immune cells, kept pumping out said cells to protect against the virus that causes COVID-19.

“We found that germinal centers were still going strong 15 weeks after the vaccine’s first dose. We’re still monitoring the germinal centers, and they’re not declining; in some people, they’re still ongoing,” he said.

“This is truly remarkable.”

According to one expert, the study’s results provide “tantalizing evidence” that booster shots of the vaccine may not need to be doled regularly, but it doesn’t really strike him as surprising.

Dr. Gerald Evans, chair of the Division of Infectious Diseases at Queen’s University, said that there’s been evidence suggesting that the “protective immunity” from contracting a coronavirus — like the common cold — could last for decades.

Several researchers have previously suggested that people who have recovered from COVID-19 before receiving a vaccination may not need a booster due to an increased presence of antibodies in their immune system against the virus.

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“So it’s kind of not surprising that the vaccines would induce these very profound what seemed to be probably prolonged immunological responses to vaccine,” said Evans.

However, according to Evans, any further changes or mutations to the virus that causes COVID-19 could potentially prevent or hinder the vaccine from what it’s supposed to do.

Such is the case with several variants of concern like the Beta variant, which appears to be more resistant to the effects of vaccines.

The upside against such variants though, Evans said, is the technology behind the Pfizer and Moderna vaccines.

mRNA vaccines can be rapidly tweaked — within six weeks — to account for protection against any new or “emerging variants,” according to Evans.

“I mean, you got to vaccinate a whole bunch of people again, you know.  But it’s not insurmountable.”