This study focused on the role of Americans’ communication about COVID-19 vaccines, and its potential associations with two significant vaccine determinants. Two studies informed by the Situational Theory of Problem Solving (STOPS) were conducted. In the first, the researchers incorporated the intention to receive vaccination against the COVID-19 pandemic and vaccine-specific knowledge into STOPS to examine the associations among these three key variables. The second study introduced a new variable, trust in science/scientists, as a potential conceptual variable that functions together with vaccine knowledge to explain why Americans’ intentions to receive COVID-19 vaccines increased despite their imperfect knowledge about them. Two online surveys were distributed using Amazon Mechanical Turk (Study 1) and Qualtrics (Study 2). The first was administered from December 18 through 22 of 2020, and the second from December 18 through 29 of 2020. An enhanced level of communicative action with respect to COVID-19 vaccines decreased the accuracy of knowledge about the vaccines, which increased the intention to receive these vaccines (Study 1). A significant interaction was also found between COVID-19 vaccine knowledge and participants’ levels of trust in science/scientists on study participants’ future intention to receive COVID-19 vaccines (Study 2). Contrary to previous findings, Americans’ increased activeness in COVID-19 vaccine-specific communication was associated negatively with vaccine knowledge, which in turn, increased COVID-19 vaccination intentions. This negative association reflects the complex and unique nature of information environments with respect to COVID-19 vaccines. Trust in science/scientists served as a significant missing conceptual variable that shed light on the paradoxical finding.