"Moderna's RSV Vaccine Efficacy Decline Sparks Stock Slide"

Moderna's shares dropped 7% as analysts expressed concerns over the faster decline in efficacy of its RSV vaccine compared to competitors GSK and Pfizer, with data showing a drop from 84% to 63% after 8.6 months. Moderna cautioned against direct comparisons, citing different trial methodologies, but analysts raised questions about the competitive profile of its vaccine. GSK and Pfizer's vaccines also showed declines in efficacy over time, with both companies exploring the possibility of at least two years of efficacy.