Respondents also showed only a slight preference for vaccines that were in development more than a year and those administered in just a single dose, leading to about a 2 percent increase in intentions, in both cases. This, too, is good news, as both the Pfizer and Moderna vaccines must be administered in two doses. They also received emergency use authorization approval in under one calendar year.
The less encouraging news, however, is that Americans are much less likely to intend to vaccinate when vaccine candidates are developed outside the U.S. Intention to vaccinate dropped by 21% for a vaccine developed in China, 18 percent for one developed in Russia, and 6 percent in the U.K. This is potentially problematic, as some leading vaccine candidates, such as AstraZeneca’s vaccine, are produced outside of the U.S.COVID-19: Americans’ Unrealistic Vaccine Expectations – The Conversation