The COVID-19 pandemic will likely recede only through development and distribution of an effective vaccine. Although there are many unknowns surrounding COVID-19 vaccine development, vaccine demand will likely outstrip early supply, making prospective planning for vaccine allocation critical for ensuring the ethical distribution of COVID-19 vaccines. Here, we propose three central goals for COVID-19 vaccination campaigns: to reduce morbidity and mortality, to minimise additional economic and societal burdens related to the pandemic and to narrow unjust health inequalities. We evaluate five prioritisation approaches, assess their likely impact on advancing the three goals of vaccine allocation and identify open scientific questions that may alter their outcomes. We argue that no single prioritisation approach will advance all three goals. Instead, we propose a multipronged approach that considers the risk of serious COVID-19 illness, instrumental value and the risk of transmission, and is guided by future research on COVID-19-specific clinical and vaccine characteristics. While we focus this assessment on the USA, our analysis can inform allocation in other contexts.