Respiratory syncytial virus (RSV) infections continue to be a public health concern, particularly for infants and older adults (65 years and older). A common upper respiratory infection that can result in hospitalizations in severe cases, RSV infection tends to be seasonal and present with symptoms similar to those of influenza and COVID-19. The occurrence of all three infectious diseases at the same time of year contributes to what public health experts call a “triple-demic,” with an associated increase in healthcare burden particularly for the most vulnerable groups. The first approvals of RSV vaccines (RSVpreF and RSVpreF3) targeted at infants and older adults mark a significant public health milestone.


  1. GSK plc
  2. Single-dose, 0.5-mL intramuscular injection for active immunization to prevent LRTD caused by RSV in individuals ≥60 years old
  3. 12 per 1,000: RSV maternal and pediatric-eligible population in the U.S.

Why is it a drug to watch?

The phase 3 results for both vaccines validate the clinical efficacy of vaccines based on the RSV F protein, which was a ground-breaking discovery that accelerated the recent development of vaccines against RSV. In addition, these results bode well for the phase 3 trial results of other assets in late-stage development, which will help support the public health initiative to reduce the RSV-related disease burden.

  • The regulatory approvals for use with older adults were based on data from the pivotal phase 3 AReSVi-006 (Adult Respiratory Syncytial Virus) trial:
  • 82.6% vaccine efficacy against RSV-LRTD
  • 94.6% vaccine efficacy against RSV-LRTD in older adults with at least one underlying medical condition of interest, such as certain cardiorespiratory and endocrine-metabolic conditions
  • 94.1% vaccine efficacy against severe RSV-LRTD, defined as an RSV-associated LRTD episode preventing normal, everyday activities

Preliminary results from the phase 3 clinical trial evaluating AREXVY for adults aged 50 to 59 years were published in October 2023, showing that the vaccine elicited an immune response in that study population that was non-inferior to that observed in adults aged 60 years and older.

Review and
approval status

February 2020

  • Fast Track designation: U.S. FDA


For the prevention of LRTD caused by RSV in individuals 60 years of age and older

May 2023

  • Approved: U.S. FDA

June 2023

  • Approved: EMA

July 2023

  • Approved: U.K. MHRA

August 2023

  • Approved: Health Canada

September 2023

  • Approved: Japan PMDA

Actual and expected launch:

  • 2023: Canada, European Union, Japan, United Kingdom, United States

How will RSVpreF3 impact the RSV market?

  1. As the first vaccine entries into an area of great unmet need, ABRYSVO and AREXVY have a competitive advantage. However, the landscape looks to become increasingly crowded, and within five years, the RSV vaccine and prophylaxis market could reach $10 billion.
  2. ABRYSVO has the advantage of a broader population that includes both older adults and pregnant individuals.
  3. AREXVY has gained approval in more of the major markets than ABRYSVO.
  4. Beyfortus™ (nirsevimab-alip; Sanofi, AstraZeneca), an MAb, is the only approved asset against RSV for children up to 2 years old (U.S. and E.U.) and offers greater flexibility in dosing than the vaccines.
  5. Other candidates in clinical development include the following:
  • ADV-110 (Beijing Advaccine Biotechnology Co Ltd): Recombinant protein vaccine for RSV
  • BLB-201 (Blue Lake Biotechnology and CyanVac LLC): Recombinant viral vector vaccine for RSV
  • CodaVax-RSV (Codagenix Inc): Live-attenuated viral vaccine for RSV
  • D46/NS2/N/deltaM2-2-Hindill (NIAID): Recombinant viral vector vaccine for RSV
  • DS-Cav1 (NIAID): Protein subunit vaccine for RSV
  • ITV-RSV-DeltaG (Intravacc): Live-attenuated viral vaccine for RSV
  • IVX-A12 (Icosavax): Virus-like particle and protein subunit vaccine for human metapneumovirus and RSV
  • MV-012-968 (Meissa Vaccines): Live-attenuated vaccine for RSV
  • MVA-BN RSV (Bavarian Nordic): Recombinant viral vector vaccine for RSV
  • mRNA-1045 (Moderna Inc): mRNA vaccine for influenza and RSV
  • mRNA-1172 (Moderna Inc and Merck): Modified mRNA-based vaccine for RSV
  • mRNA-1230 (Moderna Inc): mRNA vaccine for SARS-CoV2, influenza and RSV
  • mRNA-1345 (Moderna Inc): RNA vaccine for RSV
  • RSV 6120/deltaNS2/1030s (NIAID): Live-attenuated viral vaccine for RSV
  • RSV-276 (NIAID): Live-attenuated viral vaccine for RSV
  • RSV-F (Novavax): Protein subunit vaccine for RSV
  • RSVdeltaNS2/delta1313/1314L (NIAID): Live-attenuated viral vaccine for RSV
  • V-306 (Virometix AG): Synthetic virus-like particle vaccine for RSV
  • VN-0200 (Daiichi Sankyo): VAGA-9001a antigen; MABH-9002b adjuvant for RSV

What gaps in treatment does RSVpreF3 fill?

The search for an effective vaccine against RSV, a common, contagious virus, began in the mid-1960s but remained unsuccessful until the 2010s when focus shifted to the RSV F protein. Seasonal hospitalizations due to serious respiratory illness caused by RSV continue to be a public health issue, particularly for infants, young children, older adults and individuals with underlying health conditions such as COPD and asthma. The approvals of RSV vaccines address a significant need for infectious disease control, reduced morbidity and mortality, and decreased hospital burden at times when other infectious disease outbreaks are prevalent.

What hurdles might it need to overcome to reach blockbuster status?

Although these two vaccines were the first approved, other vaccines are in late-stage development, and Beyfortus has also been approved for use in this setting. In addition to this competition, the lag in insurance coverage in the United States during the first season in which the vaccines are available and lingering vaccine hesitancy from the COVID-19 pandemic could limit uptake.

probability of success for AREXVY in South Korea
Source: Cortellis Competitive Intelligence, Drug Timeline & Success Rates Prediction current as of November 3, 2023

Drug Timeline &
Success Rates

– Source: Cortellis Competitive Intelligence, Drug Timeline & Success Rates Prediction current as of November 3, 2023

Drugs to Watch 2024

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