An important reminder from Ian Copeland that the historical evidence on COVID mortality cannot simply be wished away. Across successive waves, age-standardized surveillance data consistently showed substantially higher COVID-19 death rates among unvaccinated populations. These are observational comparisons, and legitimate questions about confounding and healthy-vaccinee bias deserve careful examination. But those limitations do not erase the broader evidence that vaccination substantially reduced severe disease and death. The magnitude of protection varied by age, variant, prior immunity, and time since vaccination. Scientific skepticism means scrutinizing the evidence—not selectively dismissing findings because they contradict a preferred narrative. The data deserve examination, not denial.

If you engage with virus deniers on X, understand what you’re walking into. You are rarely debating one scientific claim. You’re entering a loop involving “isolation,” PCR, electron microscopy, Koch’s postulates, cell culture, sequencing—and definitions that may change whenever evidence is provided. Here’s a practical guide. 🧵