A Phase III trial demonstrated mNEXSPIKE’s non-inferior efficacy compared with Moderna’s original COVID vaccine, Spikevax.
Moderna has announced the FDA approval of a new, lower-dose messenger RNA (mRNA) vaccine against COVID-19, called mNEXSPIKE (mRNA-1283) (1). The product joins Moderna’s original COVID vaccine, Spikevax (mRNA-1273), and mRESVIA, a vaccine for respiratory syncytial virus, among the company’s properties that have been approved by FDA (1,2).
mRNA-1283 was approved, according to a May 31, 2025 press release from Moderna, for use in all adults aged 65 and older, and persons aged 12 to 64 who have at least one underlying condition putting them at high risk for severe infection as defined by the United States Centers for Disease Control and Prevention (CDC) (1).
"The FDA approval of our third product, mNEXSPIKE, adds an important new tool to help protect people at high risk of severe disease from COVID-19," said Stéphane Bancel, Moderna chief executive officer, in the press release (1). "COVID-19 remains a serious public health threat, with more than 47,000 Americans dying from the virus last year alone. We appreciate FDA's timely review and thank the entire Moderna team for their hard work and continued commitment to public health."
Approval despite changing US policies
Key Takeaways
Moderna’s mNEXSPIKE (mRNA-1283), a new COVID-19 vaccine, received FDA approval based on Phase III trial data showing higher relative vaccine efficacy than Spikevax.
The vaccine will be available for high-risk populations amid evolving US vaccination policies and public health guidance under the Trump administration.
Despite policy shifts, mNEXSPIKE is set to launch in the US for the 2025–2026 season, with comparable side effects reported relative to its predecessor, in a lower dose.
The press release did not specify whether the new vaccine targeted any specific strain of SARS-CoV-2; in May 2025, the European Medicines Agency announced it would be recommending that COVID vaccines be updated for the 2025–2026 vaccination campaign to target LP.8.1, the most prevalent variant circulating worldwide in the first half of 2025 (3). FDA had granted an emergency use authorization to both Moderna and Pfizer in August 2024 for updated versions of their mRNA vaccines that targeted the then-dominant KP.2 strain, shots that were available to the public within days of that decision (4).
But the new Moderna approval comes at a time of uncertainty for the future of US advisory policy on the administering of COVID-19 vaccines under President Donald Trump’s administration. On May 27, 2025, US Health and Human Services Secretary Robert F. Kennedy Jr. posted in a video on X announcing removal by the federal government of a recommendation that children and pregnant women get routine COVID-19 vaccines.
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"I couldn't be more pleased to announce that as of today the COVID vaccine for healthy children and healthy pregnant women has been removed from the CDC recommended immunization schedule," Kennedy said in the video (5). "We're now one step closer to realizing President Trump's promise to make America healthy again."
However, Kennedy’s disclosure reportedly blindsided CDC staff, who were not informed of the change in policy before it was publicized on social media (6). And there is somewhat more nuance to the change than what Kennedy put forth.
There is no specific recommendation for pregnant women to receive COVID-19 vaccination, as there is with certain other vaccines, according to a CDC chart (7). And the CDC’s vaccine schedule now says that the determination as to whether or not children should continue to receive the COVID vaccine should be a decision made in discussion between families and their physicians.
FDA commissioner says better studies needed
FDA Commissioner Marty Makary, MD, appeared on the CBS news program “Face the Nation” on June 1, 2025, and reiterated the new position that juvenile COVID vaccinations should be a conversation to be had between doctors and families, saying more controlled studies would be needed to offer more authoritative approval of future vaccines, and criticizing the methodology used in past CDC guidance.
“We know the CDC data is contaminated with a lot of false positives from incidental positive COVID tests with routine testing of every kid that walks in the hospital,” Makary said on the program (8).
In the case of mRNA-1283, Moderna said FDA’s approval was based on results from a Phase III trial that enrolled approximately 11,400 participants aged 12 and older, which demonstrated a 9.3% higher relative vaccine efficiency (rVE)—in a 10-μg dose—than Moderna’s previously-approved mRNA-1273 when administered in 50-μg dose (1). In adults aged 65 and older in the trial, the rVE of mRNA-1283 was 13.5%. Fewer local reactions were recorded when compared with mRNA-1273, with comparable reactions that include injection site pain, fatigue, headache, and myalgia.
Moderna said it expects to have mRNA-1283 available, under the mNEXSPIKE brand name, for its indicated populations in the US for the 2025–2026 respiratory virus season, and that the vaccine is currently under review in other nations (1). The company said mRNA-1273, or Spikevax, would still be available in the US as well.
