If the first available COVID-19 vaccine turns out to be about as effective as an annual flu shot, Americans’ enthusiasm and willingness to take it may end up falling far short of the 70% level needed to achieve herd immunity, new polls from Cornell University suggest.
In recent surveys of nearly 2,000 American adults, barely half said they would be willing to take a hypothetical vaccine with an effectiveness rate of 50%, which is the U.S. Food and Drug Administration’s minimum requirement for a COVID-19 vaccine – and also comparable to that of annual flu vaccines.
Asked whether they would take a COVID-19 vaccine that was 90% effective, its positive acceptance among those surveyed increased by 10 percentage points, to 61%.
The surveys, which were conducted in July, also asked respondents to choose between hypothetical COVID-19 vaccines based on other medical factors besides its effectiveness at preventing the virus, including how long the vaccine’s protection would last and the chances of major or minor side effects from getting the shot.
Along with improved efficacy, vaccine acceptance improved with longer-lasting virus protection (five years vs. one year) and with a lower incidence of major side effects, but by relatively small margins of 4% or less.
“Our results suggest that 50% efficacy will lead to significant vaccine hesitancy,” said Professor Douglas Kriner of Cornell. “We might not get enough people to take it at that level, even though it would be a valuable public health intervention.”