FDA and National Institutes of Health officials grappled with GOP Sen. Bill Cassidy (LA) over whether people who have previously been infected with COVID-19 need to receive the second dose of the two-dose COVID-19 vaccine regimen. Cassidy asserted that previous infection should provide enough antibody protection, but FDA biologics center director Peter Marks and National Institutes of Allergy and Infectious Diseases Director Anthony Fauci maintained the full two-dose vaccination offers a higher level of protection against the original virus and...