Evidence since 2020 strongly suggests that mRNA platforms can generate a vaccine design within days of obtaining a pathogen’s genome, and that most remaining delay is indeed due to manufacturing scale‑up, clinical trials, and regulation. For SARS‑CoV‑2, Moderna has stated that its successful vaccine candidate mRNA‑1273 was designed in about two days once the viral genetic sequence was available, and the company went from sequence to a clinical‑grade batch ready to ship for human trials in 42 days, with first‑in‑human dosing starting in March 2020 and later phase II/III trials following over subsequent months. (symposeum.us) This experience broadly validates Sacks’ claim about what the technology can do and about where the bottlenecks lie. However, his prediction is explicitly about a future highly lethal, fast‑spreading pathogen. Since late 2020 there has not been a new, clearly distinct pandemic‑scale virus of that kind; the most notable concern has been H5N1 bird flu spreading in U.S. dairy cattle and sporadically infecting humans, for which Moderna and others have developed mRNA vaccine candidates that entered clinical trials in 2024–2025, again with the main time cost in trials and regulatory work. (reuters.com) Public sources, though, do not give day‑by‑day design timestamps for these newer candidates, and the specific scenario he described (a brand‑new, highly lethal, rapidly spreading virus emerging after his prediction) has not yet occurred. Because the crucial condition for testing his forecast has not really been met, and we lack direct evidence that a future vaccine was locked in literally within one day of sequence, the safest assessment is that it is too early to say whether his prediction was fully correct or not.