First public write-up (as a preprint, later superseded by the peer-reviewed Nature paper) of China CDC’s 2020 sampling campaign at the Huanan Seafood Market: 1380 environmental + animal samples collected from 1 Jan 2020 (day of closure) through March 2020. Reports 73/923 environmental samples RT-qPCR-positive for SARS-CoV-2 (none of 457 animal-source samples positive), three live viral isolates recovered from environmental swabs, and a west-market (wildlife-stall) concentration of positives. This is the underlying primary dataset most of the market-environmental debate is fought over — the raw sequencing reads behind it were not released until over a year later (Mar 2023). relevance_note: primary record of the China CDC market environmental sampling campaign itself, prior to peer review. superseded_by: “S-16 - Liu, Gao et al. — Surveillance of SARS-CoV-2 at the Huanan Seafood Market (Nature)”