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Comment by Michael Weissman

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Condensed-matter physicist, emeritus professor at the University of Illinois, who argues proximity ascertainment bias undermines the Huanan clustering inference.
An actual previously proposed alternative theory, based on accounts of how cases were detected, was that the clustering of the unlinked cases near HSM arose from enhanced detection probability for patients living near HSM.
AI Verified (Feb 3, 2025)
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Michael Weissman, University of Illinois (Substack)
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Policy proposals and claims
The clustering of early cases around the Huanan market reflects where the COVID-19 virus emerged, not just where testing looked
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AI Verified Relevant: the quote explicitly addresses the core dispute in the statement—whether early case clustering near the Huanan market reflects the virus’s emergence location or instead an ascertainment/testing-bias effect from how cases were detected. In context, the author presents this as a substantive alternative explanation for the clustering, so a stance on the complete statement is determinable. ([michaelweissman.substack.com](https://michaelweissman.substack.com/p/big-news-on-covid-origins)) · YouCongress gpt-5.4-2026-03-05 · 1h ago
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AI Verified The quote frames the market-centered clustering as possibly arising from 'enhanced detection probability' near HSM, and the article goes on to say that if the clustering is due to ascertainment bias it 'contains no useful information about the source' and that the extent of bias is 'uncertain.' That makes the author's overall position opposed to the claim that the clustering mainly reflects where the virus emerged rather than where testing looked. ([michaelweissman.substack.com](https://michaelweissman.substack.com/p/big-news-on-covid-origins)) · YouCongress gpt-5.4-2026-03-05 · 1h ago

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AI Verified The source URL is fetchable and opens to a Substack post titled “Big News on Covid Origins” with byline “Michael Weissman” and date 2025-02-03; the submitted sentence appears in the post body at line 34, matching the quote verbatim apart from hyperlink formatting within the sentence. Weissman’s University of Illinois affiliation is also corroborated by his Illinois faculty profile. ([michaelweissman.substack.com](https://michaelweissman.substack.com/p/big-news-on-covid-origins)) · YouCongress gpt-5.4-2026-03-05 · 1h ago
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