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Sounds Strange, But There Could Be Too Many Vaccines

Nov 23 2020

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Faculty, In the News

 People confronted with many options might freeze up and choose none.

Launching dozens of vaccine development projects made perfect sense early in the Covid-19 pandemic, because it increased the chances that at least one would succeed. But what was prudent then is problematic now. Scientists, to their credit, have outdone themselves. So many vaccines may be soon be available that people will have a hard time deciding which one to get—and could end up choosing none.


The paralysis of choice is a well-known phenomenon in behavioral economics. In a famous study published in 2000, shoppers at an upscale supermarket in Menlo Park, Calif., were offered samples of jam. Some were given six choices and some were given 24. Standard economic theory says a greater number of choices is always better than a smaller selection. Indeed, customers who encountered the extensive array were more likely to stop and browse. But they were less likely to buy. Only 3% of them bought a jar of jam, vs. 30% of shoppers who encountered the limited collection.

“An extensive array of options can at first seem highly appealing to consumers, yet can reduce their subsequent motivation to purchase the product,” said the paper [PDF] by Sheena Iyengar, a professor at Columbia’s Graduate School of Business, and Mark Lepper, a psychology professor at Stanford.

The resulting paralysis could be even worse with vaccines than with jams. Vaccines are more consequential and more complicated. Pfizer-BioNTech vs. Moderna vs. AstraZeneca-University of Oxford vs. whatever else is in the pipeline is a lot harder to figure out than kiwi vs. peach vs. three-fruits marmalade (three of the concoctions that were sold in Menlo Park). 

Beyond complexity there’s fear. Surveys suggest a lot of people are nervous about taking a Covid vaccine. That may be irrational—the vaccines are undergoing extensive safety testing—but it’s a hurdle. And having multiple choices makes the hurdle that much higher.

At least in the early going, confusion is not likely to be a serious problem because supplies will be limited and most people will have only one choice, says Dr. Grace Lee, a professor of pediatrics at Stanford University School of Medicine who is a member of the Centers for Disease Control’s Advisory Committee on Immunization Practices. Later, when multiple vaccines are likely to be available in abundance, people should be guided by their doctors’ advice, she says. Your age and other characteristics may make one vaccine better for you than another. “I don’t think it’s going to be like a menu, like in a restaurant,” she says.

That’s good, because if the decision is boiled down to “Vaccine: yes/no?” a greater number of people will get a shot, herd immunity will be achieved sooner, and more lives will be saved.

((Replaces sixth paragraph with new paragraph from member of CDC’s Advisory Committee on Immunization Practices.))