By Manas Mishra and Mrinalika Roy (Reuters) -The U.S. Food and Drug Administration has raised concerns about a possible risk of heart inflammation from Novavax Inc’s COVID-19 vaccine, even as the company’s data showed it could reduce the chances of mild-to-severe disease. In Novavax’s nearly 30,000 patient trial, conducted between December 2020 and September 2021, there were four cases of a type of heart inflammation called myocarditis detected within 20 days of taking the protein-based shot. “These events raise the concern for a causal association with this vaccine, similar to the association…