Core Viewpoint - The vaccine sector is experiencing a decline in stock prices following reports of a significant policy change by the FDA, which will require all new vaccines to undergo placebo-controlled clinical trials before approval [1][2]. Group 1: Market Reaction - Major vaccine companies such as GSK, Sanofi, Merck, AstraZeneca, Pfizer, BioNTech, Moderna, and Novavax have seen stock declines ranging from over 1% to more than 3.7% [1]. - Specifically, Moderna's stock dropped over 3.7%, while BioNTech fell more than 2.5% [1]. Group 2: Regulatory Changes - The FDA plans to implement a new policy requiring all new vaccines to include a placebo group in clinical trials, marking a significant shift in the vaccine approval process [1]. - This policy mandates that new vaccines must undergo safety testing with a control group receiving an inactive substance, such as saline, for comparison [1]. Group 3: Scope of the New Policy - There is uncertainty regarding the definition of "new vaccines," but it is reported that the policy is unlikely to apply to flu vaccines, which have a long-established safety record [2]. - The HHS has not clarified whether vaccines that have already completed safety studies will be subject to re-evaluation under this new policy, focusing mainly on COVID-19 vaccines in their response [2].