USA TODAY International Edition
● Herd immunity strategy endorsed by White House “ridiculous.”
The idea that the public can infect its way out of the COVID- 19 pandemic is “a dangerous fallacy unsupported by the scientific evidence,” 80 researchers said Wednesday in a letter published in the Lancet.
They strongly denounced the idea, advocated by the White House, of achieving “herd immunity” against the virus by letting healthy people with a low risk of serious illness get infected.
A community is considered to have herd immunity when enough people build up protection against a pathogen, either through natural infection or a vaccine. For extremely contagious viruses such as the measles, about 90% of the population must be protected to prevent transmission.
There are more than 7.9 million cases and more than 217,000 deaths in the USA, according to Johns Hopkins data. Five states had a record number of deaths in a week, and 12 states set records for new cases in a week, a USA TODAY analysis found.
A memorandum published Oct. 4, called the Great Barrington Declaration, called for the world to embrace herd immunity for COVID- 19 as a way to protect the vulnerable while allowing economies to thrive.
The declaration came out of a meeting hosted by the libertarian- leaning American Institute for Economic Research. Its website says it has more than 9,000 signatures, though most names are not public. “The most compassionate approach that balances the risks and benefits of reaching herd immunity, is to allow those who are at minimal risk of death to live their lives normally to build up immunity to the virus through natural infection, while better protecting those who are at highest risk,” the declaration says.
According to The New York Times, a senior administration official, speaking anonymously, said Monday that the president has long supported the idea.
“It’s just ridiculous,” said Yvonne Maldonado, an epidemiologist and infectious disease specialist at Stanford University Medical School. “Everything they say ( in the declaration) is either misinformation or an outright lie.”
Thomas File, president of the Infectious Diseases Society of America, denounced the declaration Wednesday, saying it was “released without data or evidence.”
Herd immunity can’t work for several reasons, Maldonado said. First, no one knows how long someone who’s had COVID- 19 remains immune.
“We know that the natural history of coronavirus infections is that people can get reinfected over and over again,” she said. In one case, a 25- year- old man from Nevada was infected in late March and five weeks after recovering was diagnosed again with a slightly different version of the virus.
The idea that it’s possible to isolate high- risk people is absurd, Maldonado said.
“Over 40% of the U. S. population has some risk. I don’t know how you are going to keep 40% of the population away from the other 60%,” she said.
Though younger people are at “minimal risk of death,” as the declaration reads, it’s by no means a zero chance.
Trying to reach herd immunity would result in a much higher death rate than the USA is experiencing, said George Rutherford, an infectious disease specialist at the University of California- San Francisco.
“What we’re talking about here is a disease in which you probably need to get somewhere in excess of 60% of people with permanent – not temporary – immunity,” he said. “It’s just not attainable without a much greater mortality than we’ve had so far.”
Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, told a college class at the Massachusetts Institute of Technology last month that it’s not clear what percent of the population would need to be infected to provide herd immunity from COVID- 19, though it’s likely to be 50% to 75% of the public.
“We’re not anywhere near there yet,” he said. “If already, 200,000 people have died and you want to let things go to get herd immunity, you’re going to get a lot of suffering and a lot of deaths. If we get herd immunity, let’s get it with a vaccine and not by letting everybody get infected.”
By definition, when herd immunity is reached, infections should decline. Even in the hardest hit areas of New York City, where one- quarter to onethird of residents may have been infected in the spring, infection rates are rising.
“That’s the only thing you need to know that herd immunity has not been reached,” said William Hanage, a Harvard epidemiologist.
In areas where the virus raged earlier in the year, lower rates of infection are the result not of herd immunity but changes in people’s behavior, said Stephen Kissler, a research fellow in the Department of Immunology and Infectious Diseases at Harvard T. H. Chan School of Public Health.
“It is crystal clear that there are still enough susceptible people in the population even in major parts of New York City to sustain outbreaks,” he said. “What we do see are vast differences in people’s responses to the pandemic and the precautions people are taking.”
Critics said that instead of pushing for herd immunity, the Trump administration should promote public health measures known to be safe and effective: wearing masks, washing hands, avoiding large groups, maintaining social distance and providing easily accessible testing and contact tracing.
The Lancet letter, called the “John Snow Memorandum,” notes countries that mounted a robust public health response to the virus, including Japan, Vietnam and New Zealand, effectively controlled transmission.
“We cannot afford distractions that undermine an effective response,” said the 80 signatories.
John Snow, a Victorian physician, is considered the father of epidemiology. He tracked the source of a London cholera epidemic to a contaminated water well in 1854. He removed the pump handle, so no one could get water from the well – a controversial move at the time – and the epidemic ended.
Monday, World Health Organization head Tedros Adhanom Ghebreyesus called herd immunity not just unscientific but unacceptable. “It’s not a choice between letting the virus run free and shutting down our societies,” he said.
Herd immunity, Ghebreyesus said, is possible only through vaccination, which safely protects a large enough portion of the population to keep the virus from spreading. Letting the virus circulate unchecked would mean unnecessary infections, suffering and death. “Never in the history of public health has herd immunity been used as a strategy for responding to an outbreak, let alone a pandemic,” Ghebreyesus said. “Allowing a dangerous virus that we don’t fully understand to run free is simply unethical.”