During the COVID-19 pandemic, which triggered a worldwide emergency call to pursue new drugs and devices to treat and cure the disease, vaccines began to be developed mid-2020, as a promising weapon and shield. Fiocruz, a Brazilian government science and technology institute, signed a public procurement for innovation contract with the foreign pharmaceutical company AstraZeneca to purchase, at that time, vaccines still under development. It was the first public procurement for innovation contract in the Brazilian public health system (SUS). This paper analyzes how the Brazilian public procurement contracts for the COVID-19 vaccine dealt with technology and institutional risks and uncertainties. It also aims to describe how such agreements (and the legal apparatus behind them) relate to the Brazilian system of innovation and to the theoretical approach of contracting for innovation. A key question is: how does the public procurement for innovation vaccine contract signed by Fiocruz deal with the intrinsic nature of uncertainty that characterizes innovation, and what lessons and challenges can be drawn?