Core Viewpoint - The U.S. CDC has adopted new recommendations for RSV vaccinations, lowering the age for eligible recipients, which has positively impacted Moderna's stock price and expanded its market potential for the RSV vaccine, mResvia [1][7]. Group 1: CDC Recommendations - The CDC has revised its recommendations to include adults aged 50-59 at higher risk of severe illness from RSV, advising them to receive a single dose of the vaccine [2][8]. - Previously, the guidance recommended vaccination for individuals aged 75 and older, and those aged 60-74 who were at high risk [2][8]. - The current HHS secretary, Robert F. Kennedy, Jr., officially adopted these recommendations, filling the role of CDC director, which is currently vacant [3]. Group 2: Impact on Moderna - The expanded CDC recommendations increase the addressable market for Moderna's RSV vaccine, mResvia, by including a new segment of eligible patients aged 50-59 [7][8]. - Despite the initial approval of mResvia for individuals aged 60 and older, the FDA recently expanded its label to include high-risk individuals aged 18-59 [9]. - Sales of mResvia have been modest since its commercial launch last year, as it was approved later in the contracting season compared to GSK's and Pfizer's vaccines [9][10]. Group 3: Competitive Landscape - Moderna is competing with GSK and Pfizer, both of which have already received approvals for their RSV vaccines for individuals aged 60 and older, with GSK's Arexvy also approved for high-risk individuals aged 50-59, and Pfizer's Abrysvo approved for high-risk individuals aged 18-59 [11]. - The earlier availability of GSK and Pfizer's vaccines has given them a dominant position in the market over Moderna [10]. Group 4: Stock Performance - Year to date, Moderna's stock has lost 27%, while the industry has only seen a 2% decline [5].

Group 1: Regulatory Developments - GSK announced that the European Medicines Agency (EMA) has accepted the regulatory application for the expanded use of its RSV vaccine, Arexvy, for adults aged 18 years and above, with a final decision expected in the first half of 2026 [1] - Arexvy is currently approved for individuals aged 60 years and above and high-risk individuals aged 50-59 years [2][7] Group 2: Sales Performance - Arexvy generated sales of £78 million in the first quarter of 2025, reflecting a 57% year-over-year decline due to lower demand in the United States [8][7] - Year to date, GSK shares have risen 20.8%, contrasting with a 0.6% decline in the industry [4] Group 3: Market Context - Other RSV vaccine makers include Pfizer's Abrysvo, which is approved for individuals aged 60 years and above and high-risk adults aged 18-59 years [9] - Moderna's RSV vaccine, mResvia, was approved for older adults and is also being expanded for high-risk adults aged 18-59 years [11] - The overall RSV vaccine market has seen weak sales for the 2024-2025 vaccination season, attributed to restrictive recommendations from the U.S. CDC [12]