Doctor recommendations and parents' HPV vaccination intentions in Kenya: A randomized survey.

The causal effect of a doctor's recommendation for Human Papillomavirus (HPV) vaccination on parents' decisions in low-resource settings is not well understood. This study investigates how doctors' endorsement of the HPV vaccine communicated through a public health poster affects parents' decisions to vaccinate their daughters in Kenya. In January and February 2021, 600 parents of daughters eligible for the HPV vaccine but not yet vaccinated were recruited and completed a randomized survey. Participants saw a poster from a national campaign about HPV vaccination and either nothing further (Control) or an additional poster containing an HPV vaccine recommendation from a female (FDR) or male doctor (MDR). Primary outcomes are intentions to vaccinate and perceived safety of the HPV vaccine. Both recommendation arms increased the likelihood that participants reported the highest levels of vaccine intentions compared to control (FDR: 33.7% p = 0.01; MDR: 30.5%, p = 0.05, compared to Control (22.4%)) and safety perceptions (FDR: 24.2%. p = 0.09; MDR: 28.0%, p = 0.01, compared to Control (17.1%)) but there was no statistically significant increase in the likelihood to report above moderate vaccine intentions (FDR: 72.6%, p = 0.76; MDR: 72.5%, p = 0.77, compared to Control (71.4%)) or safety perceptions (FDR: 68.9%, p = 0.91; MDR: 75.0%, p = 0.17, compared to Control (68.6%)). We find no differential treatment effect by the recommending doctor's gender. In conclusion, our results suggest that visual communication of a doctor's support for the HPV vaccine can strengthen above-moderate intentions and safety perceptions but may not be enough to persuade the vaccine hesitant to vaccinate.