Read: What you need to know about the coronavirus
The 1976 flu vaccine, like every seasonal flu vaccine, was at least based on a previous version, tweaked to protect against the current year’s strains. A COVID-19 vaccine, in contrast, would be completely new. “With vaccines, unlike many other products—like iPhones—novelty is not necessarily a desirable characteristic,” says Bruce Gellin, the president of global immunization at the Sabin Vaccine Institute. Although vaccine researchers have been able to leverage research on related coronaviruses that cause MERS and SARS to get a COVID-19 vaccine into clinical trials quickly, no human coronavirus vaccine has ever been approved. The novelty of such a vaccine could make even people without reservations about other vaccines hesitate.
A COVID-19 vaccine would also enter a world where the pandemic itself has been deeply politicized, where simply wearing or not wearing a mask, for example, can be seen as a political act. In 2017, Asheley Landrum and Dan Kahan wrote a paper considering the introduction of Gardasil, the vaccine for the human papillomavirus (HPV), in what they called a “polluted” science-communication environment. Gardasil was fast-tracked for approval in 2006, which at first limited its use to girls and young women, for whom the risk of cervical cancer from HPV warranted an expedited process. But this choice also landed the vaccine in the middle of a culture war over the sexuality of young girls. (Six years and much controversy later, Gardasil was also approved for males in 2009.) “It’s a great example of something that didn’t have to be politically polarizing, but because of the way it was introduced into the public sphere, you have political polarization,” Landrum says. “It’s clearly the same thing that happened here with COVID-19.”
Vaccine skepticism is not especially partisan, and it draws from elements of both the left and the right. But the politicization of COVID-19 could affect skepticism of a COVID-19 vaccine asymmetrically. A recent Reuters/Ipsos poll found that 24 percent of Americans have little or no interest in getting a coronavirus vaccine. When asked about a scenario in which President Trump affirmed that the vaccine was safe, 14 percent said they would be more interested, but 36 percent said they would be less interested.
How exactly a COVID-19 vaccine will be received is likely to depend on its perceived risks and benefits, which will depend on its effectiveness and the point in the pandemic cycle at which it arrives. The 1976 vaccine debacle was, after all, exacerbated by the fact that the feared flu pandemic didn’t happen; the risks of the vaccine clearly outweighed the benefits.
“Expectations are astronomically high as vaccines are now positioned as the only way we can get back to normal,” Gellin says. “If they aren’t 100 percent effective, or are significantly less, there is bound to be disappointment, and that might also extend to perceptions about vaccines more generally.” While most childhood vaccinations such as those for measles and polio are more than 90 percent effective, the seasonal flu vaccine is usually only 40 to 60 percent effective. You can still get the flu—if probably in a milder form—after you get a flu shot. This is one of the reasons why convincing people to get flu vaccines is so hard in the first place. Because of how the coronavirus infects the respiratory tract, and how immunity against coronaviruses specifically works, a COVID-19 vaccine might mitigate but not prevent the disease.