Illustration: Phil Foster

There are many lessons to be gleaned from the U.S. pandemic response. House Democrats don’t care to study them.

The House Select Subcommittee on the Coronavirus Crisis last month issued a deeply partisan report demonizing doctors who purportedly espoused “a dangerous and discredited herd immunity via mass infection strategy.” The report took aim at the Trump administration’s embrace of the October 2020 Great Barrington Declaration, in which epidemiologists Martin Kulldorff (Harvard), Sunetra Gupta (Oxford) and Jay Bhattacharya (Stanford) advocated protecting the elderly and vulnerable while allowing schools and businesses to reopen. This wasn’t a strategy to infect masses of people on purpose. The goal was to minimize deaths and social and economic harm until the country reached herd immunity through infection or vaccination.

The Great Barrington strategy of “focused protection” helped minimize the pandemic’s collateral damage until vaccines became available. The Biden administration then undertook a strategy of herd immunity via vaccination. But when this strategy failed, it doubled down with vaccine mandates.

From the outset of the pandemic, the mainstream medical establishment and government bureaucracy were aligned behind a lockdown-at-all-costs strategy. The Trump White House tapped Scott Atlas, a Hoover Institution fellow and radiologist, for a contrarian perspective. Dr. Atlas endorsed the elements of the Great Barrington strategy. The House report criticizes him for a memo in which he argued that “stopping all cases is not necessary, nor is it possible. It instills irrational fear into the public. Non-prioritized testing is jeopardizing critical resources for truly critical testing and is creating problematic delays in test results for the most important populations.”

He was right on every point. Indiscriminate use of a scarce resource reduces public welfare. When tests were in short supply, Dr. Atlas’s recommendation to save them for high-risk groups such as nursing-home residents made eminent sense. His prescriptions and those of the Great Barrington Declaration aimed to maximize public welfare.

Democrats claim in their report that 130,000 lives could have been saved with more “mitigation,” but this is doubtful. California and New York, which adopted mask mandates and lockdowns during the 2020-21 winter, fared no better than Florida and Texas, which didn’t. What’s more, employment continues to lag significantly in liberal lockdown states. Had all 50 states stayed shut down until vaccines were available, with the federal government paying tens of millions of people not to work—as Democrats ostensibly would have done—we might now be experiencing high unemployment and even higher inflation.

Vaccines ultimately saved the day by reducing the Covid disease burden and giving Democratic states a reason to lift their destructive lockdowns. But the Biden administration bet too heavily on vaccines to confer herd immunity. In December 2020, Anthony Fauci projected that a 75% to 85% vaccination rate could provide a “blanket of herd immunity.” This proved too optimistic.

An ever-mutating and increasingly transmissible virus, combined with waning vaccine effectiveness, made herd immunity a moving target. By spring 2021, Pfizer’s clinical trial data showed that its vaccine was becoming less protective against infection as time passed. Four months after the second dose, vaccine efficacy had declined to 84%, making breakthrough infections more likely and imperiling the Biden administration’s goals. Yet Pfizer honcho Albert Bourla writes in his new book, “Moonshot,” that federal public-health officials feared disclosing this waning efficacy would breed more vaccine hesitancy. The Biden administration kept it under wraps until July, when breakthrough infections in Provincetown, Mass., made it impossible to deny. Stories in the media were corroborated by a study from Israel the same month showing vaccine protection against infection falling to 39%.

Only after the Washington Post published a leaked Centers for Disease Control and Prevention slide presentation showing that vaccine efficacy was declining did the agency acknowledge it. Still, Dr. Fauci in August insisted that herd immunity could be achieved “really easily if we get everyone vaccinated.” He should have known by then that was false.

None of these realities stopped the Biden administration from mandating vaccines for private workers and arguing in court, despite evidence to the contrary, that doing so was “necessary to protect unvaccinated workers from the risk of contracting COVID-19” and “that vaccines dramatically reduce the risk of contracting and transmitting COVID-19.” After the Supreme Court blocked the mandate in January, the administration pivoted to a strategy of focused protection—e.g., distributing antiviral and monoclonal-antibody treatments and booster shots to the vulnerable. Alas, the administration’s orders were too little, too late to help when deaths and hospitalizations soared in winter 2021-22.

Nearly 600,000 Covid deaths have occurred on Mr. Biden’s watch despite vaccines and better treatments—about 180,000 more than under Donald Trump. One lesson is the importance of diverse opinions. The Biden administration paid too much heed to experts such as Dr. Fauci and ignored those who argued against placing all its eggs in the vaccine basket.

Another lesson is that science evolves, and there’s no shame in admitting error. Most scientists were wrong about what it would take to achieve herd immunity. But it’s better to correct mistakes than compound them, which is what the Biden administration did. Why it did is something for a future GOP Congress to investigate.

Ms. Finley is a member of the Journal’s editorial board.