Natural origins favored: study finds pandemic viruses can jump to humans without pre-adaptation

A UC San Diego‑led genomic analysis of Ebola, Marburg, mpox, influenza A, and SARS‑CoV‑2 finds no evidence that most pandemic viruses required adaptation in an animal reservoir or in a lab before infecting humans; selection changes usually appear after human transmission. The study does note a possible lab‑linked signal for the 1977 H1N1 influenza and cites palm civet–associated SARS‑CoV as a historical example, but argues SARS‑CoV‑2 likely arose through natural zoonotic transmission. The authors stress that distinguishing natural spillovers from lab mishandling relies on genomic signals and call for strengthened surveillance and spillover prevention to prepare for future pandemics, challenging theories that COVID‑19 was lab‑engineered.