Moderna's RSV Vaccine Efficacy Declines Faster Than Rivals, Stock Drops by 7%

Moderna, a leading biotechnology company, recently faced a 7% drop in its stock value following concerns over the declining effectiveness of its experimental respiratory syncytial virus (RSV) vaccine. Comparisons with rival vaccines from GSK and Pfizer have highlighted a faster decline in Moderna's vaccine efficacy, stirring concerns amongst Wall Street analysts and impacting the firm's stock performance.

Analysts' Concerns Over Moderna's RSV Vaccine

Analysts at Cowan studied follow-up data from Moderna’s Phase 3 mRNA vaccine trial for RSV. They discovered that its efficacy dwindles faster than vaccines produced by GSK and Pfizer. Specifically, Moderna's vaccine saw a 25% decline in efficacy after 8.6 months, while GSK observed a 7% decline after 14 months. Despite initial data showing Moderna's experimental vaccine to be as effective as GSK’s and perhaps more so than Pfizer’s in the first six months, these recent findings have raised concerns over the long-term performance of Moderna's RSV vaccine.

Comparing Efficacy with Rival Vaccines

Further data reveals a decrease in Moderna's RSV vaccine efficacy from 84% at 3.3 months to 63% after 8.6 months. In comparison, GSK's Arexvy saw a fall to 77% at 14 months from 83%, while Pfizer's vaccine slipped to 49% in 17 months from 67%. Moderna has cautioned against such comparisons, stating that the trials for the rival shots used different case definitions for RSV-disease. However, analysts maintain their concerns over the competitive profile of Moderna's shot if these findings are confirmed with more data. GSK and Pfizer are both exploring the possibility of at least two years of efficacy for their vaccines.

The Future of Moderna's RSV Vaccine

Moderna's RSV vaccine, mRNA-1345, may require more frequent booster shots due to its faster declining efficacy. This could potentially impact its market position, especially as the RSV vaccine market becomes increasingly competitive with new contenders like Arcturus Therapeutics entering the field. Despite these concerns, Moderna has submitted global regulatory filings for mRNA-1345 in RSV prevention for those aged 60 and older, expecting approvals to begin in the first half of 2024.

Market Impact and Future Outlook

The declining efficacy of Moderna’s experimental RSV vaccine underscores the competitive nature of vaccine development. It also illustrates the significant impact of analyst assessments on stock performance. Given the current landscape, Moderna’s shares fell as much as 7% on the concerns raised over the quicker decline in the efficacy of its vaccine. The future market position of Moderna's RSV vaccine may depend on the need for more frequent booster shots compared to its rivals, which could potentially affect its long-term market position. However, ongoing research and development in the vaccine market promise better solutions in the near future, keeping the competition open and dynamic.