Moderna announced Thursday that its combination flu and COVID-19 vaccine faces significant regulatory delays, with approval now potentially pushed to 2026 instead of the expected decision this year. The Food and Drug Administration has requested additional Phase 3 flu efficacy data before considering approval of the shot, which would be the first in the US to offer protection against both viruses in a single administration.
The company had filed for approval based on late-stage study results showing the vaccine, designated mRNA-1083, elicited immune responses against both influenza and coronavirus in adults 50 years and older. However, the FDA's request for more comprehensive efficacy data represents a potential shift in the regulatory landscape for vaccine developers.
Regulatory Environment Shifts
Moderna executives emphasized that interactions with the FDA have remained "business as usual" despite recent leadership changes at the Department of Health and Human Services (HHS) and FDA. Stephen Hoge, Moderna's president, stated during an analyst call that the agency's request for additional flu efficacy data "makes good scientific sense."
"We continue to have productive exchanges across all of our ongoing reviews," Hoge said. "Our responsibility as a manufacturer and drug developer is to make sure that we provide the data that regulators and public health officials feel like they need so that they can stand behind our products."
However, Wall Street analysts view the delay differently. Leerink Partners analyst Mani Foroohar wrote that the news "highlights increased scrutiny and (potentially) a higher bar for success in vaccine development – especially novel vaccines," which could "negatively impact" the regulatory path for Moderna's combination shot.
The delay follows an unusual regulatory postponement for fellow COVID-19 vaccine developer Novavax and comes as HHS indicates new shots will need to be tested in placebo-controlled trials prior to regulatory approval.
Combination Vaccine Technology and Benefits
Moderna's mRNA-1083 represents an important advancement in vaccination technology. If approved, it would streamline the vaccination process by offering protection against two significant respiratory viruses in a single shot.
Dr. Rituparna Das, Moderna's vice president of respiratory development, highlighted the potential benefits: "We are excited about the potential for 1083 as a combination vaccine that could improve protection against flu and COVID in a single shot. For the past several years, it has been these two respiratory viruses which caused challenges for hospital systems in the fall."
In June, Moderna released trial data showing the combination vaccine was safe and elicited higher immune responses against influenza virus and coronavirus than currently licensed seasonal flu and COVID-19 vaccines in adults 50 and older.
Combination vaccines are already common in pediatrics, with the measles-mumps-rubella (MMR) vaccine and the DTaP vaccine (for diphtheria, tetanus, and pertussis) being widely used examples.
mRNA Technology Faces Political Headwinds
The delay comes amid growing concerns about anti-vaccine sentiment potentially affecting regulatory decisions. Unlike Novavax's protein-based COVID-19 vaccine, Moderna's combination shot uses mRNA technology, which has become a target of political opposition despite its proven safety and efficacy.
Several states have introduced measures to ban the administration of mRNA vaccines, including Montana, Iowa, Idaho, and Texas, though some of these efforts have been defeated or remain under review.
"Legislative efforts to ban or restrict mRNA medicines in various states are largely driven by misunderstandings about their well-established safety profile and mechanism of action," said Moderna spokesperson Jenna Sexton. "For example, while mRNA does not modify DNA, this misconception is frequently cited in support of such policies."
Dr. Peter Hotez, co-director of the Texas Children's Hospital Center for Vaccine Development, expressed concern about the political climate: "This is playing out now in some state legislatures that are trying to ban mRNA vaccines because of disinformation from the anti-vaccine lobby saying that they integrate into our DNA, that they cause turbo cancers, that they inflate the side effects."
Potential Impact on Public Health
If eventually approved, a flu-COVID combination vaccine could help improve vaccination rates by simplifying the process for patients. Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center, noted that "you only have to roll up one sleeve to get your vaccine, and you can get two at the same time and get good, solid protection as recommended."
Market research suggests significant demand exists for such a product, with Novavax reporting that "greater than 60% of consumers stating a preference for an all-in-one option," according to Silvia Taylor, the company's executive vice president.
The mRNA technology used in these combination vaccines could also potentially address limitations in current seasonal flu vaccination programs. Traditional flu shots are developed months in advance to target expected dominant strains, but by the time vaccines are administered, different strains may be circulating.
"You can make a piece of mRNA very quickly, and possibly closer to the actual fall-winter flu season," Hotez explained. "With mRNA, we could delay that decision on what goes into the vaccine – maybe for a couple of months, until May or so – until we have a better idea of what's circulating."
Financial Implications for Moderna
The regulatory delay comes at a challenging time for Moderna, which is already facing declining product sales and a falling stock price. The company has announced plans to cut $1.5 billion in annual spending by 2027 and is deprioritizing development of the combination vaccine in younger adults as part of this cost-cutting initiative.
Moderna recorded $108 million in revenue in the first quarter of the year, down from $167 million in the same period last year. The company's shares fell approximately 5% following the announcement and have lost about half their value over the past six months.
The upcoming regulatory decisions on Moderna's new COVID shot and expanded use of its respiratory syncytial virus vaccine in younger adults, both expected by mid-June, are being viewed by analysts as "litmus tests" for the current regulatory environment for vaccines.
