Market Chatter: Moderna, Merck Shares Drop After Potential Data Leak for Melanoma Vaccine

01:32 PM EDT, 10/22/2026 (MT Newswires) -- Moderna (MRNA) and Merck (MRK) shares were down 24.7% and 3.4%, respectively, at 1:20 pm ET, after reports emerged about a possible leak of data on the companies' highly anticipated personalized melanoma vaccine, Bloomberg reported Thursday, citing unverified sources on X. Moderna and Merck didn't immediately reply to requests for comment from MT Newswires. (Market Chatter news is derived from conversations with market professionals globally. This information is believed to be from reliable sources but may include rumor and speculation. Accuracy is not guaranteed.) Price: 186.46, Change: -59.35, Percent Change: -24.14