Big chunks of the history of the Covid pandemic were rewritten over the last month or so in a way that will have terrible consequences for many years to come.

Under questioning by a congressional subcommittee, top officials from the National Institutes of Health, along with Dr. Anthony Fauci, acknowledged that some key parts of the public health guidance their agencies promoted during the first year of the Covid-19 pandemic were not backed up by solid science. What’s more, inconvenient information was kept from the public — suppressed, denied or disparaged as crackpot nonsense.

Remember the rule that we should all stay at least six feet apart? “It sort of just appeared,” Fauci said during a preliminary interview for the subcommittee hearing, adding that he “was not aware of any studies” that supported it. Remember the insistence that the virus was primarily spread by droplets that quickly fell to the floor? During his recent public hearing, he acknowledged that to the contrary, the virus is airborne.

As for the repeated assertion that Covid originated in a “wet market” in Wuhan, China, not in an infectious diseases laboratory there, N.I.H. officials were privately expressing alarm over that lab’s lax biosafety practices and risky research. In his public testimony, Fauci conceded that even now there “has not been definitive proof one way or the other” of Covid-19’s origins.

Officials didn’t just spread these dubious ideas, they also demeaned anyone who dared to question them. “Dr. Fauci Throws Cold Water on Conspiracy Theory That Coronavirus Was Created in a Chinese Lab” was one typical headline. At the hearings, it emerged that Dr. David Morens, a senior N.I.H. figure, was deleting emails that discussed pandemic origins and using his personal account so as to avoid public oversight. “We’re all smart enough to know to never have smoking guns, and if we did we wouldn’t put them in emails and if we found them we’d delete them,” he wrote to the head of a nonprofit involved in research at the Wuhan lab.

I wish I could say these were all just examples of the science evolving in real time, but they actually demonstrate obstinacy, arrogance and cowardice. Instead of circling the wagons, these officials should have been responsibly and transparently informing the public to the best of their knowledge and abilities.