Moderna falls after RSV vaccine shows 50% efficacy after 18 months

Moderna’s (MRNA) respiratory syncytial virus shot mRESVIA showed 50% efficacy in preventing RSV after 18 months, the company announced at a meeting of the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices, reports Reuters. In their clinical trials, GSK’s (GSK) RSV vaccine Arexvy was 78% effective in preventing severe RSV over a second year and Pfizer’s (PFE) was 78% effective midway through a second RSV season, Reuters points out. Moderna previously cautioned against comparing its vaccine to rivals, noting that the trials were not head-to-head and used different case definitions for RSV disease, it adds. Shares of Moderna are down 6% to $129.36 in morning trading.