There is existing evidence of a relationship between media use and vaccine hesitancy. Four online questionnaires were completed by general population samples from the US and the UK in June 2020 (N = 1198, N = 3890, N = 1663, N = 2237). After controls, all four studies found a positive association between intention to be vaccinated and usage of broadcast and print media. The three studies which operationalised media usage in terms of frequency found no effect for social media. However, the study which operationalised media use in terms of informational reliance found a negative effect for social media. Youth, low household income, female gender, below degree-level of education, and membership of other than white ethnic groups were each also found to be associated with lower intentions to be vaccinated in at least two of the four studies. In all four studies, intention to be vaccinated was positively associated with having voted either for Hillary Clinton in the 2016 US presidential elections or for Labour Party candidates in the 2019 UK general election. Neither of the UK studies found an association with having voted for Conservative Party candidates, but both US studies found a negative association between intention to be vaccinated and having voted for Donald Trump. The consistent finding of greater intention to be vaccinated among users of legacy media but not among users of social media suggests that social media do not currently provide an adequate replacement for legacy media, at least in terms of public health communication. The finding of a negative association with social media in the study which measured informational reliance rather than frequency is consistent with the view that uncritical consumption of social media may be acting to promote vaccine hesitancy.