Covid-19 | Herd immunity? Or ‘mass murder’?

A proposal to let people with low risk of infection live without constraint could lead to a million or more preventable deaths.

No matter their politics, people nearly always listen to those who say what they want to hear.

Hence, it is no surprise that the White House and several governors are now paying close attention to the “Great Barrington Declaration,” a proposal written by a group of well-credentialed scientists who want to shift Covid-19 policy toward achieving herd immunity — the point at which enough people have become immune to the virus that its spread becomes unlikely.

They would do this by allowing “those who are at minimal risk of death to live their lives normally.” This, they say, will allow people “to build up immunity to the virus through natural infection, while better protecting those who are at highest risk. We call this Focused Protection.”

These academics are clearly a distinct minority. Most of their public health colleagues have condemned their proposal as unworkable and unethical — even as amounting to “mass murder,” as William Haseltine, a former Harvard Medical School professor who now heads a global health foundation, put it to CNN last week.

But who is right?

The signers of the declaration do have a point. Restrictions designed to limit deaths cause real harm, including, but by no means limited to, stress on the economy, increases in domestic violence and drug abuse, declines in tests that screen for cancer and on and on. Those living alone suffer real pain from isolation, and the young have every reason to feel bitter over the loss of substantive education and what should have been memories of a high school prom or the bonding friendships that form in a college dorm at 2 a.m. or on an athletic team or in some other endeavor.

So the idea of returning to something akin to normal — releasing everyone from a kind of jail — is attractive, even seductive. It becomes less seductive when one examines three enormously important omissions in the declaration.

First, it makes no mention of harm to infected people in low-risk groups, yet many people recover very slowly. More serious, a significant number, including those with no symptoms, suffer damage to their heart and lungs. One recent study of 100 recovered adults found that 78 of them showed signs of heart damage. We have no idea whether this damage will cut years from their lives or affect their quality of life.

Second, it says little about how to protect the vulnerable. One can keep a child from visiting a grandparent in another city easily enough, but what happens when the child and grandparent live in the same household? And how do you protect a 25-year-old diabetic, or cancer survivor, or obese person, or anyone else with a comorbidity who needs to go to work every day? Upon closer examination, the “focused protection” that the declaration urges devolves into a kind of three-card monte; one can’t pin it down.

Third, the declaration omits mention of how many people the policy would kill. It’s a lot.

The Institute for Health Metrics and Evaluation at the University of Washington, whose modeling of the pandemic the White House has used, predicts up to about 415,000 deaths by Feb. 1, even with current restrictions continuing. If these restrictions are simply eased — as opposed to eliminating them entirely, which would occur if herd immunity were pursued — deaths could rise to as many as 571,527. That’s just by Feb. 1. The model predicts daily deaths will still be increasing then.

Will we have achieved herd immunity then? No.

Herd immunity occurs when enough people have immunity either through natural infection or a vaccine so the outbreak eventually dies out. By Feb. 1, even with eased mandates, only 25 percent of the population will have been infected, by my calculations. The most optimistic model suggests herd immunity might occur when 43 percent of the population has been infected, but many estimate 60 percent to 70 percent before transmission trends definitively down.

Those are models. Actual data from prison populations and from Latin America suggest transmission does not slow down until 60 percent of the population is infected. (At present, only about 10 percent of the population has been infected, according to the C.D.C.)

And what will be the cost? Even if herd immunity can be achieved with only 40 percent of the population infected or vaccinated, the I.H.M.E. estimates that a total of 800,000 Americans would die. The real death toll needed to reach herd immunity could far exceed one million.

As horrific a price as that is, it could prove much worse if damage to the heart, lungs or other organs of those who recover from the immediate effects of the virus does not heal and instead leads to early deaths or incapacitation. But we won’t know that for years.

Some aftereffects of the 1918 influenza pandemic did not surface until the 1920s or later. For instance, children born during its peak in 1919 had worse health outcomes as they grew older, compared with others born around that time. There is speculation that the influenza caused a disease called encephalitis lethargica, which became almost epidemic in the 1920s and then later disappeared, and which affected patients in Oliver Sacks’s book “Awakenings.” Both the 1918 pandemic and other viruses have been linked to Parkinson’s disease.

Proponents of herd immunity point to Sweden. Swedish officials deny having actively pursued that strategy, but they never shut down their economy or closed most schools, and they still haven’t recommended masks. Its neighbors Denmark and Norway did. Sweden’s death rate per 100,000 people is five times Denmark’s and 11 times Norway’s. Did the deaths buy economic prosperity? No. Sweden’s G.D.P. fell 8.3 percent in the second quarter, compared with Denmark’s 6.8 percent and Norway’s 5.1 percent.

Finally, the Great Barrington Declaration aims at a straw man, opposing the kind of large, general lockdown that began in March. No one is proposing that now.

Is there an alternative? There was once a simple one, which the vast majority of public health experts urged for months: social distancing, avoiding crowds, wearing masks, washing hands and a robust contact tracing system, with support for those who are asked to self-quarantine and for selected closures when and where necessary.

Some states listened to the advice and have done well, just as many schools listened and have reopened without seeing a surge. But the Trump administration and too many governors never got behind these measures, reopened too many states too soon, and still haven’t straightened out testing.

Worse, the White House has all but embraced herd immunity and has also poisoned the public with misinformation, making it all but impossible to get national, near-universal compliance with public health advice for the foreseeable future.

As a result, the United States is not in a good place, and achieving near containment of the virus — as South Korea (441 deaths), Australia (904 deaths), Japan (1,657 deaths) and several other countries have done — is impossible. We can, however, still aim for results akin to those of Canada, where there were 23 deaths on Friday, and Germany, which suffered 24 deaths on Friday.

Getting to that point will require finally following the advice that has been given for months. That will not happen with this White House, especially since it is now all but openly advocating herd immunity, but states, cities and people can act for themselves.

Nothing, including monoclonal antibodies, rapid antigen testing, or even a vaccine, will provide a silver bullet. But everything will help. And hundreds of thousands of Americans will keep living who would otherwise have died under a policy of herd immunity.

(John M. Barry is a professor at the Tulane University School of Public Health and Tropical Medicine and the author of “The Great Influenza: The Story of the Deadliest Pandemic in History.”)