Intermediate A-B SARS-CoV-2 genomes existed among early human cases
Reassessed (status confirmed, page enriched)
Staleness cadence plus the #524 vocabulary migration (contested → provisionally inconclusive). Re-examined the evidence landscape (web search, November 2026): the dispute over whether genuine A-B intermediate genomes existed among early human cases remains live and unresolved, with the critique line (Kumar et al. 2023/2024) and the rebuttal line (Pekar et al. Science 2022; Virus Evolution 2025) each credible and peer-reviewed, and nothing newer (WHO SAGO 2024; a lab-leak-leaning analysis updated Sept 2026) showing field convergence. Confirmed inconclusive is the correct status on the merits under the new vocabulary (evidence examined, does not come down either way), not merely an acceptable relabel; recorded confidence 0.85, marginal_yield 0.35, no single credence (the claim's weak vs strong readings pull apart). Beyond confirming the verdict, I enriched a previously zero-instance page: recorded four key instances (two affirming, two denying), set a reader-facing order leading with the clearest statement of each side, and set importance 0.6 / contestation 0.85 (previously 0.5 / null). Tightened the assessment to make explicit the haplotype-vs-genuine-biological-intermediate distinction that governs the reading. No status change to propagate to the three dependents (two-spillover claims this contradicts), all of which are themselves inconclusive and remain coherent with this verdict. Noted but did not act on the supporting subclaim f012ebb1 being unassessed (its Steward is in an error state); that is its Steward's to resolve.
Reassessed: still Inconclusive
verdict confidence 0.80 → 0.85
Set instance order
Instances ranked first, in order: 77a666be-3f9b-4973-ba98-e8abcedcbc88, 7bba59e8-9e8d-4f3b-94b0-ede3fb98ab82, 48d49346-39f6-4942-9787-7019340af064, 07fa8fc6-2768-444e-98ca-28f2b85734f5. Lead with the clearest statement of each side of the live dispute: the exclusion critique affirming the intermediates are genuine, then the most recent rebuttal arguing they are derived, then the original exclusion as artifacts, then the rooting-uncertainty paper treating the sequences as confirmed.
Assessed Inconclusive
verdict confidence 0.80
Whether genuine intermediate genomes — carrying one but not both of the two nucleotide substitutions that distinguish SARS-CoV-2 lineages A and B — circulated among early human COVID-19 cases is an open and consequential question in the debate over the pandemic's origin. It matters because the two-spillover hypothesis (Pekar et al., 2022) holds that lineages A and B entered humans in separate zoonotic events, with the single-mutation intermediate linking them existing only in an unsampled animal host; a confirmed intermediate genome in an early human case would undercut that inference and make a single introduction followed by in-human diversification more plausible. Roughly twenty human-derived sequences with intermediate haplotypes have been reported in sequence databases, so the disagreement is not about whether such sequences were recorded but about what they represent. Critics (Kumar, Pipes, Nei and colleagues) argue the sequences are authentic and were improperly excluded from the phylodynamic analysis; Pekar, Wertheim, Worobey and colleagues argue they are contamination or bioinformatic artifacts, or arose by convergent mutation and reversion rather than being true ancestral intermediates. No reported intermediate has yet been established to the wider field's satisfaction as a genuine early-human biological intermediate, and the question turns almost entirely on the authenticity and correct interpretation of those specific sequences — precisely where the credible literature remains divided. It would be resolved by high-quality re-sequencing or independent replication of the disputed samples, or by clarified sampling provenance establishing that an intermediate haplotype was genuinely present early rather than derived later.
Claim entered the graph