Romanian MEP Terheş why would Ursula sign a €71 billion contract with Pfizer?

Romanian MEP Cristian Terheş asks why Ursula von der Leyen would sign a €71 billion contract with Pfizer to buy 4.6 billion vaccine doses (10 doses per citizen). https://x.com/CraigKellyPHON/status/1804469759267754260