Study: How mRNA-1345 RSV Vaccine Compares to Previously Approved RSV Vaccines

Researchers from University of Illinois in Chicago assessed key differences among the 3 approved respiratory syncytial virus (RSV) vaccines—RSVPreF3 (Arexvy; GSK), RSVpreF (Abrysvo; Pfizer,) and mRNA-1345 (mRESVIA; Moderna). The study authors noted that health care providers should be aware of current information on each vaccine to aid patient recommendations on RSV immunizations.¹

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The CDC describes RSV as a common respiratory virus that causes mild, cold-like symptoms, severely impacting infants and older adults. The virus is often spread airborne, through sneezing or coughing, as well as direct contact and contaminated surfaces. RSV hits its peak season in the winter in the US; however cases can begin as early as the fall, according to study authors. Cases among older individuals could result in hospitalization as patients may need oxygen, intravenous fluids, intubation, or mechanical ventilation. To avoid severe RSV infection, the CDC and the Advisory Committee on Immunization Practices (ACIP) recommend all adults aged 60 years and older to receive a single dose RSV vaccine, through shared clinical decision-making.^1,2

The FDA previously approved RSVPreF3 and RSVpreF in May 2023 to protect individuals 60 years and older against RSV-associated lower respiratory tract diseases (LRTD). Following the approval, the FDA updated the use of RSVpreF to also treat pregnant individuals.¹

However, in May of this year, the FDA approved mRNA-1345 as an additional RSV vaccine to treat adults 60 years and older, which will be available during the 2024-2025 RSV season, according to study authors. The approval was based on positive results from the ConquerRSV trial that displayed lower incidence of RSV-LRTD and RSV-associated acute respiratory disease with mRNA-1345, compared to a placebo.³ Despite its recent approval, the CDC did not yet update recommendation guidelines for mRNA-1345, emphasizing the need for up-to-date information to ensure health care providers and deliver patients with proper recommendations.¹

"The FDA approval of our second product, mRESVIA, builds on the strength and versatility of our mRNA platform," Stéphane Bancel, CEO of Moderna, said in a news release. "mRESVIA protects older adults from the severe outcomes of RSV infection, and it is the only RSV vaccine available in a pre-filled syringe designed to maximize ease of administration, saving vaccinators' time and reducing the risk of administrative errors. This approval is also the first time an mRNA vaccine has been approved for a disease other than COVID-19."³

The study authors noted that the key difference among all 3 vaccines include its mechanism of protection. The mRNA-1345 vaccine in a “lipid nanoparticles-encapsulated mRNA-based vaccine encoding the RSV fusion (F) glycoprotein stabilized in the prefusion (preF) conformation.” Differing from this, RSVPreF3 and RSVpreF are non-mRNA vaccines. Additionally, RSVPreF3 and PSVpreF are in vials that include lyophilized powder as mRNA-1345 is a single-dose prefilled syringe—offering more convenience. While the dosing is similar among all 3 vaccines, the study authors noted that the antigen component delivered is different. Lastly, both RSVPreF3 and RSVpreF were reported to cause cases of atrial fibrillation and Guillain-Barré syndrome but were not observed with mRNA-1345. However facial paralysis occurred in 1 case with mRNA-1345.¹

The findings suggest that all 3 vaccines provide RSV-LRTD protection for adults 60 years and older, however, the mRNA-1345 vaccine provides a one-off mechanism of protection because of its single-dose prefilled syringes, according to study authors.¹

References

1. What information is available on the newly approved Moderna RSV vaccine (mRESVIA®) and how does it compare with other currently available RSV vaccines? University of Illinois Chicago. News release. July 2024. Accessed August 5, 2024. https://dig.pharmacy.uic.edu/faqs/2024-2/july-2024-faqs/what-information-is-available-on-the-newly-approved-moderna-rsv-vaccine-mresvia-and-how-does-it-compare-with-other-currently-available-rsv-vaccines/

2. CDC. About RSV. June 5, 2024. Accessed August 5, 2024. https://www.cdc.gov/rsv/about/index.html.\

3. Gallagher A. FDA Approves mRNA-1345 for Protection Against Lower Respiratory Tract Disease Caused by RSV. Pharmacy Times. News release. May 31, 2024. Accessed August 5, 2024. https://www.pharmacytimes.com/view/fda-approves-mrna-1345-for-protection-of-lower-respiratory-tract-disease-caused-by-rsv