The U.S. Food and Drug Administration (FDA) announced new regulatory guidelines for COVID-19 vaccine boosters on Tuesday, establishing stricter approval standards for Americans. The FDA hopes to see new clinical trials proving that COVID-19 vaccines remain safe and effective before approving them for healthy adults and children. Related NewsTrump Says He's Willing to Visit CN to Discuss Diplomatic & Economic Issues with XiThis will be a costly new requirement for pharmaceutical companies and may limit the number of new vaccines administered each year.The news bolstered vaccine stocks, with Moderna (MRNA.US) up 6%, and BioNTech (BNTX.US) and Novavax (NVAX.US) up 1-2%. (Real-time Streaming US Stocks Quote; Except All OTC quotes are at least 15 minutes delayed.)