Moderna's RSV Vaccine Efficacy Declines Faster Than Rivals: Insights from Phase 3 Trial

In the race for a Respiratory Syncytial Virus (RSV) vaccine, Moderna's mRNA-1345 shows a faster decline in efficacy compared to its rivals, Pfizer and GlaxoSmithKline (GSK). The Phase 3 trial data reveals a 25% decrease in efficacy from Moderna's RSV vaccine, raising concerns about its durability and its competitive position in the market.

Moderna's RSV Vaccine Efficacy: A Closer Look

According to TD Cowen, Moderna's mRNA-1345 vaccine against RSV has a faster fall in efficacy compared to the shots from Pfizer and GSK. The vaccine showed an overall efficacy of 63.3% against two-symptom RSV disease at a median follow-up of 8.6 months, down from the initial reported efficacy of 84%. In contrast, FDA-approved RSV shots from GSK/Agenus and Pfizer did not indicate such a rapid decline in efficacy. Consequently, TD Cowen maintains a Market Perform rating on Moderna amid concerns about the potentially faster decline in its RSV vaccine efficacy.

Comparative Efficacy: Moderna vs. Pfizer and GSK

Focusing on the comparative data, Moderna's vaccine showed a 25% drop in efficacy after 8.6 months. On the other hand, GlaxoSmithKline's vaccine reported a smaller 7% decline after 14 months, and Pfizer showed varied results. This indicates that Moderna's vaccine may need more frequent booster shots, potentially impacting its market position in the long run.

RSV Vaccine Market Dynamics

The RSV vaccine market is seeing increasing competition with new contenders entering the field. For instance, Arcturus Therapeutics, in partnership with CSL Seqirus, has developed a self-amplifying mRNA (saRNA) COVID-19 vaccine, ARCT-154, that demonstrated extended immunity at 3 and 6 months post-booster dose. The saRNA vaccine platform, unlike the traditional mRNA vaccines, instructs the body to make more mRNA and protein to boost the immune response. This innovation might set a new precedent for future RSV vaccines.

Future Outlook for Moderna's RSV Vaccine

Despite the concerns raised, Moderna has submitted global regulatory filings for mRNA-1345 in RSV prevention for those aged 60 and older. The company expects approvals to begin in H1 2024. As the vaccine market continues to evolve, it remains to be seen how these developments will shape the competitive landscape. However, the key takeaway for consumers is the importance of regular booster doses to maintain the efficacy of these vaccines.

Understanding RSV

Respiratory Syncytial Virus (RSV) is a common respiratory virus that causes mild, cold-like symptoms. However, it can be severe, especially for infants and older adults. RSVPreF3 OA, a candidate vaccine for older adults, showed 71.7% efficacy against RSV ARI and 82.6% efficacy against RSV LRTD in a phase 3 trial, highlighting the critical need for effective vaccines in combating this virus.

In conclusion, while Moderna's RSV vaccine shows a faster decline in efficacy compared to its rivals, the ongoing research and developments in the vaccine market promise better solutions in the near future.