Why It’ll Take More Than One Vaccine to Beat COVID-19on September 11, 2020 at 7:00 pm

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In the rush of the COVID-19 vaccine “race,” it’s easy to forget one important detail: There might be several winners.

It’s too early to tell which or how many candidates will make it to market, which means some of the administrative protocols or requirements are unknown, too. “As results start to become clear, we will then have that kind of a situation where we’ll have more certainty about what’s going on and how that will impact vaccination policy,” says Saad Omer, epidemiologist and director of the Yale Institute for Global Health.

In other words, it’s only after the first vaccine (or vaccines) receive approval that heath officials and policymakers can nail down logistics of how to get people vaccinated. Plus, no matter how good the initial vaccine options are, it may take additional options to help nationwide vaccination campaigns run smoother and faster.

For starters, slower-to-market vaccines could have higher efficacy rates. Again, it’s still not clear if this will be the case. And if this scenario does pan out, it doesn’t mean that the first vaccine will be ineffective. The FDA has set an expectation that any COVID-19 vaccine would block the disease or reduce illness severity in at least 50 percent of people who get it. Maybe the first option available will blow past the minimum expectation, Omer says. But if it doesn’t, then there’s still value in pursuing vaccines that are more likely to convey immunity to their recipients.

There’s also a future scenario in which the first vaccine works well in younger people, but drops in efficacy for the elderly, says William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center. Aging immune systems can struggle to develop strong responses to vaccines, and seniors might need modified formulas to up the odds that they will be protected from getting ill.

For a COVID-19 vaccine, whether or not older people would need a different vaccine is still unknown, Omer emphasizes — there hasn’t been enough data yet from the various vaccines in development to determine whether they convey equal odds of immunity across all age groups. But the possibility means there could be room for formulas that work better for that portion of the population.

Enhanced options for the elderly already exist for some viruses. A seasonal flu vaccine approved only for people over 65 has four times the virus-like component, for example. Manufacturers can also add molecules called adjuvants as a way to improve likelihood of vaccination success. “Adjuvants can stimulate an immune system to function as if it were younger,” says Schaffner. Already, labs are researching adjuvants that, when added to a vaccine, kick off the best immune response possible, regardless of age.

Several leading COVID-19 vaccine candidates might also require people to get two doses. People receive several injections for a single preventative treatment all the time. The HPV vaccine, for example, requires two or three shots depending on your age. But as vaccination efforts roll out, single-dose options are easier on the supply chain — that’s one syringe per person, not two — and let people arrange time for a medical visit just once.

There’s also the question of how different COVID-19 vaccines might reach people. A couple frontrunners in development need to be kept at super cold temperatures — we’re talking -4 degrees Fahrenheit for the Moderna candidate and -94 F for the two vaccines from a BioNTech and Pfizer collaboration.

Medical centers are used to keeping vaccines cold. But current CDC recommendations for optimal freezer temperatures only go as low as -58 F, which means many clinics likely aren’t set up to store these vaccines.

Manufacturers and shipping companies are working hard to assemble enough deep freezers for distribution needs, which should be doable for the entire U.S. “It’s not a rocket science-level technology,” Omer says. “It’s expensive, but it can be done.” An extreme cold requirement could become a larger issue in nations with a less-developed power infrastructure, so in those places, a less-deep-freeze-dependent vaccine could eliminate major barriers to vaccination programs.

Of course, one of the largest challenges to vaccinating people against COVID-19 is each individual’s willingness to participate. And right now, the federal education plan on the pandemic and COVID-19 vaccines specifically amounts to the CDC website, says Omer. “We don’t have a national vaccine communication strategy,” he says, “and that blows my mind.” Without a concerted education effort, it could be challenging to convince people to go get their injection — let alone remind them if they’ll need to go back for a second.

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