Moderna’s mRNA-based flu and covid-19 vaccine could provide the best of both worlds—if it’s actually ever approved by the Food and Drug Administration.
This week, scientists at Moderna published data from a Phase III trial testing the company’s combination vaccine, codenamed mRNA-1083. Individuals given mRNA-1083 appeared to generate the same or even greater immune response compared to those given separate vaccines, the researchers found. But the FDA’s recent policy change on vaccine approvals, orchestrated by Health Secretary Robert F. Kennedy Jr, could imperil the development of this and other future vaccines.
The trial involved 8,000 people split into two age groups: those between the ages of 50 and 64, and those over 65. People were randomly given mRNA-1083 (plus a placebo) or two already approved flu and covid-19 vaccines.
The vaccine seemed effective across both age groups, with mRNA-1083 participants showing at least the same level of humoral immune response (antibody-based) to circulating flu and covid-19 strains as participants who were given the separate vaccines.
On average, this response was actually higher to the flu strains in particular among those given mRNA-1083. The experimental vaccine also appeared to be safe and well-tolerated, as the authors explained in their paper, published Wednesday in JAMA.
The study results are certainly encouraging, and typically they would pave the way toward a surefire FDA approval. But the political situation has changed for the worse. The Department of Health and Human Services recently mandated an overhaul of the vaccine approval process, one that will require all new vaccines to undergo placebo-controlled trials to receive approval.
While many experimental vaccines today are placebo-tested (including the original covid-19 vaccines), it’s unclear whether this order will also apply to vaccines that can be compared to existing vaccines, like the combination mRNA-1083 vaccine, or to vaccines that have to be regularly updated to match fast-evolving viruses like the flu and covid-19.
Some vaccine experts have said that these changes are unnecessary and potentially unethical, since it could leave some people vulnerable to an infection that already has a vaccine.
The new rule also might delay the availability of upcoming seasonal vaccines, particularly the current covid-19 shots.
A potentially important wrinkle for the mRNA-1083 vaccine is that no mRNA-based vaccine for the flu is currently approved. That reality could very well be all that the FDA needs to demand further placebo-controlled trials. RFK Jr. and other recent Trump appointees have also been highly skeptical of mRNA-based vaccines in general, despite no strong evidence that these vaccines are significantly less safe than other types. Kennedy, who has a long history of supporting the anti-vaccination movement, has even wrongly declared that the mRNA covid-19 vaccine was the “deadliest vaccine ever made.”
Moderna stated last week it doesn’t expect its mRNA-1083 vaccine to be approved before 2026, following the FDA’s request for late-stage data showing the vaccine’s effectiveness against flu specifically. But it’s worth wondering if even that timeline is now in jeopardy under the current public health regime.