Moderna and Merck are surging today after the two companies said their experimental mRNA-based treatment succeeded in a late-stage study of high-risk melanoma patients.

But this isn't just a Moderna-and-Merck rally. The SPDR S&P Biotech ETF $(XBI)$ jumped nearly 5%, while the NYSE Arca Pharmaceutical Index climbed over 3%.

That's unusual. A positive clinical-trial result typically moves the companies developing the drug-and perhaps their closest competitors-not the entire healthcare sector.

The answer may be that mRNA has come to represent something bigger than mRNA itself. During the pandemic, healthcare and biotech stocks soared on the belief that vaccines and breakthrough technologies were ushering in a new era of medical innovation. In mid-2021, Moderna's market value reached about $150 billion, nearly as much as Merck's.

Then the pandemic ended. The political backlash arrived, along with disappointing post-Covid mRNA demand and a series of setbacks that crushed Moderna and Pfizer-and helped turn parts of the biotech industry into a political and market bogeyman.

That's why today's news matters beyond Moderna and Merck. Yes, it's a major result for melanoma patients. But investors appear to be reading it as something broader: evidence that the industry is capable of delivering the kind of breakthrough medicines that made biotech one of the hottest corners of the market in 2020 and 2021.

And it's perhaps a reminder to policymakers and a skeptical public of what the industry is capable of when the science works.