Primary care physicians (PCPs) are among the most trusted sources of health information and play a key role in shaping patients’ health behaviors. However, it remains unclear how influential physician recommendations are in highly politicized health contexts, where exposure to health information and trust in health care authorities, including PCPs, vary widely.

We conducted an online survey experiment (n = 1,494) with U.S. adults recruited through Prolific. Participants were randomly assigned to one of six experimental conditions that varied (1) whether an antiviral Covid treatment was prescribed by their own PCP or another physician and (2) which treatment options were available. Participants then reported their willingness to take treatment under different levels of Covid-19 symptom severity.

Demand for antiviral treatment was low when symptoms were mild but increased sharply with symptom severity. Treatment endorsement by a participant’s own PCP substantially increased treatment uptake (by about 60 percent) among vaccinated individuals in mild-symptom scenarios. In contrast, PCP endorsement had no detectable effect on unvaccinated participants, who also reported significantly lower trust in PCPs.

PCPs can play an important role in increasing willingness to take effective treatments to address a polarized health issue, such as Covid-19. However, in such contexts, PCPs may have difficulties impacting the willingness to take effective treatments in groups where PCP trust is particularly low. This suggests a need for strategies to restore and increase trust between healthcare providers and populations that are particularly skeptical of medical guidance.