In her interview on CBS Face the Nation, Dr. Leana Wen raised concerns about the potential threat of bird flu, citing a "mortality rate" of 52% based on historical outbreaks. However, this figure is not a true mortality rate, which measures deaths from a disease relative to the total population. Instead, it represents the case fatality rate (CFR) — the percentage of reported cases that result in death. Specifically, between January 2003 and May 2024, the World Health Organization recorded 889 cases of H5N1 and 463 deaths, giving a CFR of 52%. This distinction is crucial because some viewers might mistakenly believe that 52% of the entire population (not just diagnosed cases) would die if exposed to bird flu. In reality, the mortality rate depends on how many people are infected in the population and how deadly the disease is. If bird flu infects only a small fraction of the population, the overall mortality rate would be much lower than the CFR. By presenting the CFR as a "mortality rate," Dr. Wen risks creating undue alarm, especially without clarifying that bird flu has not yet become a widespread human disease and remains difficult to transmit between humans. Dr. Wen also highlighted concerns about mutations in the virus that could increase its ability to infect humans, emphasizing the need for testing and vaccine preparedness. While these are valid points, framing the 52% CFR as an imminent public health crisis lacks critical context. Most human cases have involved individuals with close contact with infected birds, not general population exposure. Moreover, recent U.S. cases have been mild, highlighting the variability in disease outcomes.