Moderna shares jumped more than 16% on Friday, May 8, after peer-reviewed Phase 3 data confirmed its mRNA flu vaccine candidate outperformed traditional shots in older adults — a result that arrived just as a deadly hantavirus outbreak on a cruise ship drew fresh attention to the company’s early-stage work on a hantavirus vaccine.
Flu Vaccine Milestone
The rally was triggered by the publication in the New England Journal of Medicine of results from Moderna’s Phase 3 trial (P304) evaluating mRNA-1010, its seasonal influenza vaccine candidate. The study enrolled more than 40,700 adults across 301 sites in 11 countries during the 2024-25 flu season and found the mRNA vaccine achieved a relative vaccine efficacy of 26.6% over a licensed standard-dose flu shot in adults aged 50 and older. The vaccine also showed consistent performance across individual strains — 29.6% against A/H1N1, 22.2% against A/H3N2, and 29.1% against B/Victoria — and maintained an rVE of 27.4% among participants 65 and older.
Moderna announced on May 6 that regulatory filings are under review in the United States, Europe, Canada, and Australia, with the FDA’s PDUFA goal date set for August 5, 2026. If approved, mRNA-1010 would become the company’s second commercial respiratory vaccine after its RSV shot, mResvia.
Hantavirus Connection
The stock received an additional lift from renewed interest in Moderna’s hantavirus vaccine research. Korea University’s Vaccine Innovation Center and Moderna have been collaborating on an mRNA-based hantavirus vaccine since signing a research agreement in September 2023 under Moderna’s mRNA Access initiative. A research team confirmed in February 2025 that experimental doses prevented hantavirus infection in mice, according to Seoul Economic Daily.
The partnership gained wider attention this week as a hantavirus outbreak aboard the cruise ship MV Hondius dominated headlines. As of May 4, the World Health Organization reported eight cases — three confirmed and five suspected — including three deaths, among the 147 people aboard. The ship, which departed Ushuaia, Argentina, on April 1, is now en route to Spain’s Canary Islands.
Analysts Urge Caution on Hantavirus Hype
Despite the stock’s surge, analysts stressed that Moderna’s hantavirus candidate remains in preclinical stages. The Korea University team has said human clinical trials have been on hold for more than a year awaiting funding of 10 to 20 billion won to produce clinical-grade material. Prediction markets assigned an 87.5% probability that no hantavirus vaccine would be approved in 2026, citing the absence of any Phase 3 candidates globally.
Heading into Thursday’s rally, Moderna’s stock had already been rebuilding from its pandemic-era lows, trading near $48.54 as of May 6. The company reported first-quarter 2026 revenue of $389 million and has drawn growing investor interest in its oncology pipeline. For the flu vaccine news, the more immediate catalyst, the question now is whether the FDA grants approval by August — a decision that could reshape Moderna’s commercial outlook well beyond COVID-19.
