This policy brief reports findings from two nationally representative online surveys that were conducted in the United States (N=2,280) and in the United Kingdom (N=2,000) in October and November 2020 to explore the factors that influence the willingness to be vaccinated against Covid-19. The study was conducted before vaccines were officially approved and on the market. However, it very closely tracks the actual developments in both countries through the summer of 2021. Findings suggest that socioeconomic factors, some very difficult to influence by policy in the short term, strongly shape the willingness to be vaccinated. In addition, the contested and divided political landscape and the highly competitive and fragmented media system in the United States help explain the findings.The surveys identify similarities but also major differences between the two countries. In the United States, 51% of the adult population said they were willing to be vaccinated against COVID-19, 28% were not, and 21% were undecided. In the United Kingdom, 71% of the adult population said they were willing to be vaccinated, 14% were not, and 15% were undecided. Race may be a major barrier to achieving high COVID-19 vaccination rates in the United States. Black respondents were 46% less willing to be vaccinated than White respondents. Gender may be a barrier to achieving high vaccination rates in the United States and United Kingdom. Women were 43% less willing to be vaccinated than men in the United States. They were 41% less willing than men to be vaccinated in the United Kingdom.Older individuals and those with higher income indicated a higher willingness to be vaccinated in both countries. Trust appears key to vaccination acceptance. Individuals with higher levels of trust in mass media were more willing to be vaccinated in both countries. Individuals with a higher general level of trust in others were more willing to be vaccinated in the United States. Medical information. Individuals who consulted medical sources were more willing to be vaccinated. Media sources. Reliance on conservative outlets, mainstream outlets, and television was not associated in a statistically significant way with the willingness to be vaccinated. Concern about getting COVID-19 is strongly associated with willingness to get vaccinated. Individuals who were more concerned about the pandemic indicated they were more willing to be vaccinated, but this effect was much stronger in the United Kingdom than in the United States.Overall, in the United States, the factors most strongly associated with willingness to be vaccinated are race (White), gender (male), age (older), income (higher), trust in mass media, and concern about getting coronavirus. In the United Kingdom, the factors most strongly associated with willingness to be vaccinated are gender (male), age (older), income (higher), trust in mass media, and concern about getting coronavirus. Race is not associated with the willingness to be vaccinated, unlike in the United States
