COVID-19 vaccinations have demonstrated effectiveness in reducing severe infections. However, vaccine hesitancy posed a major public health hurdle to combat the COVID-19 pandemic. Online spread of vaccine conspiracy beliefs generated unwarranted mistrust and resistance to vaccines. While numerous studies have explored the factors influencing vaccine hesitancy, there remains a lack of comprehensive understanding regarding the interplay between perceived disease vulnerability, COVID-19 fear, and vaccine hesitancy. Protection motivation theory posits citizens will evaluate perceived threats and take actions to mitigate potential harm. With a large U.S. sample, path analysis demonstrated individuals' perceived disease vulnerability was associated with lower vaccine hesitancy. Greater perceived disease vulnerability was associated with higher COVID-19 fear. Greater COVID-19 fear was associated with lower vaccine hesitancy. Greater vaccine conspiracy beliefs associated with higher vaccine hesitancy. However, in the presence of perceived vulnerability to disease, vaccine conspiracy beliefs associated with higher fear of COVID-19 and thereby lower vaccine hesitancy. We found under circumstances of higher perceived vulnerability to disease and fear of COVID-19, vaccine conspiratorial believers were less vaccine hesitant. We discuss how public health messaging can highlight personal risks to contracting COVID-19 to appeal to those who self-identify as disease prone, but may have reservations about vaccines because of misinformation. Successfully combating diseases entails reaching and gaining cooperation from misbelievers because misinformation is expected to continue in the digital age. By understand individual differences to vaccine hesitancy, it can help increase vaccinations and prevent severe illnesses in the post COVID-19 pandemic era.