MARIA CAROLINA MARCELLO A Brazilian congressman who has denounced alleged wrongdoing in a 1.6 billion reais ($323 million) COVID-19 vaccine contract signed by Brazil's government arrived at a Senate commission inquiry wearing a bullet-proof vest for safety. Congressman Luis Miranda and his brother Luis Ricardo Miranda, the whistleblower at the Health Ministry who raised suspicions about the vaccine deal with India's Bharat Biotech, are the key witnesses in a hearing underway on Friday. The parliamentary inquiry is looking into the government's handling of the coronavirus pandemic that has killed more than half a million people in Brazil, and accusations that…