Chris Green is concerned about the potential misuse of electronic vaccine passport systems. He notes that it should be up to individual countries to make decisions regarding such measures, respecting other nations' choices and considering their own actions accordingly. Green highlights the effectiveness of vaccination programmes but argues that any certification must be proportionate to the current threat level of diseases, which is currently diminishing. He expresses comfort with paper-based vaccine certificates but raises significant questions about data protection and civil liberties if electronic systems are employed.