Moderna, Inc. (MRNA) shares plummeted 6.37% during intraday trading on Monday, marking a sharp reversal from recent gains.

The decline follows a significant six-session rally of 39% that had pushed the stock to its highest level since the previous September. Analysts point to profit-taking pressure as a primary driver, with investors locking in gains after the substantial run-up. Recent positive catalysts, including a unanimous FDA advisory committee vote recommending approval of the company's mRNA-based seasonal influenza vaccine for older adults and potential manufacturing expansion plans, appear to have been fully priced into the stock.

Sentiment was further weighed down by analyst skepticism. Leerink Partners maintained its Underperform rating on Moderna despite raising its price target, signaling continued caution. Barclays also maintained a Hold rating. With the FDA's final approval decision on the flu vaccine not expected until early August, the market is entering a period with fewer near-term catalysts, exacerbating the profit-taking pressure.