It feels like there's light at the end of the tunnel: States are beginning to relax or eliminate COVID-19 restrictions. The Centers for Disease Control and Prevention (CDC) issued guidelines for vaccinated Americans to ease back into post-pandemic life. And President Joe Biden has ordered states to open vaccinations to all adults by May 1.
Yet that light could be snuffed out by the sordid fact that multiple coronavirus strains are circulating throughout the United States — strains that existing vaccines were not designed to combat, and which in some cases may outsmart the vaccines. The CDC has repeatedly expressed concern that the mutated viruses will lead to a surge in COVID-19 cases as some of them are able to evade vaccines.
Of course, new vaccines can certainly be invented, and existing ones tweaked, to combat said mutations. But that brings up the unpleasant logistical prospect that we may need multiple vaccines, perhaps even yearly boosters, to protect ourselves as the disease evolves.
"It is highly possible that we'll need a booster shot," Dr. Irwin Redlener, leader of Columbia University's Pandemic Response Initiative, told Salon. "In fact, we may end up even needing an annual booster shot because we don't know really how long the antibodies are going to last from the shot or from the natural disease for that matter. It's in the cards."
Such a prospect is not unprecedented for a nascent virus. Doctors do the same with influenza, for which new strains emerge annually; those new strains often evade previous vaccines just enough that annual flu shots are necessary to combat them.
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But as Redlener noted, vaccine manufacturers are aware of the problem and are already working on it.
"Moderna has been working on a booster shot to help respond to variants for at least a month," Redlener explained. "I'm sure that Pfizer and J&J and the other manufacturers are all doing the same. It's imperative that we pay attention to those variants."
Dr. William Haseltine, chair and president of the global health think tank Access Health International, reinforced this perception, adding that the question of COVID-19 booster shots is in some respects independent of whether or not variants emerge.
"It's very likely that whether or not there were variants, we would need a third booster and annual boosters because the primary immunity from these vaccines is unlikely to last over a year or a year-and-a-half," Haseltine explained."We have no idea at this point what the duration is, but if it is like many other vaccines in this category, it's unlikely to be very long lived with a half-life, I would guess, of somewhere around three to six months. That means that even if there weren't variants, you would need a booster."
Immunologists use the terms "durable immunity" and "transient immunity" to refer to the type of immunity that a vaccine confers. If a vaccine confers short-term immunity, it is said to have transient immunity. If a vaccine keeps one's immune system primed and ready to fight a disease over the long term, then it said to provide durable immunity. The influenza vaccine is an example of a vaccine that confers transient immunity, which is another reason that annual shots are needed. It is still not known whether the coronavirus vaccine will confer transient or durable immunity; if it is sufficiently transient, regular boosters will become a necessity.
Dr. Russell Medford, chairman of the Center for Global Health Innovation, told over email Salon that regular vaccine booster shots will help reinforce the immune response, which can wane over time. Medford also said that vaccine technology had advanced to the point that boosters could be "rapidly developed" to target viral variants that "exhibit significant resistance to existing vaccines."
Fortunately, new vaccine technologies have made it easier to quickly adapt existing vaccines. New vaccine technologies like mRNA vaccines make it "fairly easy" for new vaccines to be developed as variants emerge that threaten the public health. This is because, while conventional vaccines like the kind created by Johnson & Johnson take a weakened or dead form of the disease-causing microorganism and inject it into your body, mRNA vaccines use a more adaptable approach. Scientists create synthetic versions of mRNA, a single-stranded RNA molecule that complements one of the DNA strands in a gene. After they do that, they inject a version of the mRNA into your body so your cells will produce proteins like those found in a given pathogen (in this case, the SARS-CoV-2 virus that causes COVID-19). One advantage to this approach is that it is easier to create new mRNA vaccines as the viruses evolve.
Not every expert is worried that we will need new vaccines for COVID-19 variants. Dr. Monica Gandhi, an infectious disease doctor and professor of medicine at the University of California–San Francisco, referred Salon to a recent thread she wrote in which she expressed optimism that the current vaccines will protect us from COVID-19 in the long term.
"I don't think that we will need a new vaccine for variants each year although the pharmaceutical companies are working on these boosters now just to show they can," Gandhi wrote to Salon, referring both to the aforementioned thread. She added that studies have found T cell immunity, or a form of immunity that occurs after a virus has entered the body, persists against known COVID-19 variants.