The US Food and Drug Administration (FDA) has refused to review Moderna's application for approval of a new flu vaccine.[1] The company conducted a clinical study on 40,000 people that compared the new vaccine with a commonly used flu vaccine.[1] The study concluded that the new vaccine is slightly more effective than the standard vaccine in adults 50 years of age and older.[1] The FDA called the study inadequate because it did not compare the vaccine to the best available standard of care in the US at the time of the study.[1] According to Moderna, the FDA previously approved the original study design and provided feedback that the use of the selected standard vaccine was acceptable.[1] However, according to the FDA, the company did not accept the recommendations of the office from the administration of President Joe Biden.[1] Critics warn that the move could jeopardize broader vaccine development.[1]