Moderna's flu data offer a clear lesson: mRNA isn't magic

Last fall, as their Covid-19 vaccine crossed the finish line, Moderna unveiled plans to take its newly proven mRNA platform and use it to effectively change how the world blocks humanity’s most persistent viral foes.

In addition to their pre-existing vaccine programs, executives announced new ones for flu, where vaccines have chronically underperformed, and HIV, which has eluded every inoculation effort over nearly 40 years. In flu, the other mRNA vaccine companies — BioNTech (with Pfizer), Translate Bio (under Sanofi), and CureVac (with GSK) — all had similar ambitions, hoping to make shots that were as high as 80% effective.

Friday morning, though, cast doubt on those lofty hopes. Moderna became the first company to release data on an mRNA flu candidate, and they looked, well, fine.