In late December 2019, eight pages of genetic code were sent to computers at the National Institutes of Health in Bethesda, Md.

Unbeknown to American officials at the time, the genetic map that had landed on their doorstep contained critical clues about the virus that would soon touch off a pandemic.

The genetic code, submitted by Chinese scientists to a vast public repository of sequencing data run by the U.S. government, described a mysterious new virus that had infected a 65-year-old man weeks earlier in Wuhan. At the time the code was sent, Chinese officials had not yet warned of the unexplained pneumonia sickening patients in the central city of Wuhan.

But the U.S. repository, which was designed to help scientists share run-of-the-mill research data, never added the submission it received on Dec. 28, 2019, to its database. Instead, it asked the Chinese scientists three days later to resubmit the code with certain additional technical details. That request went unanswered.

It took almost another two weeks for a separate pair of virologists, one Australian and the other Chinese, to work together to post the genetic code of the new coronavirus online, setting off a frantic global effort to save lives by building tests and vaccines.

The initial attempt by Chinese scientists to publicize the crucial code was revealed for the first time in documents released on Wednesday by House Republicans investigating Covid’s origins. The documents reinforced questions circulating since early 2020 about when China learned of the virus that was causing its unexplained outbreak — and also drew attention to gaps in the American system of monitoring for dangerous new pathogens.