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Date: December 03, 2020 06:23PM
It's not like the mumps or chicken pox.
https://www.nature.com/articles/d41586-020-02948-4The false promise of herd immunity for COVID-19
Why proposals to largely let the virus run its course — embraced by Donald Trump’s administration and others — could bring “untold death and suffering”.
In May, the Brazilian city of Manaus was devastated by a large outbreak of COVID-19. Hospitals were overwhelmed and the city was digging new grave sites in the surrounding forest. But by August, something had shifted. Despite relaxing social-distancing requirements in early June, the city of 2 million people had reduced its number of excess deaths from around 120 per day to nearly zero.
In September, two groups of researchers posted preprints suggesting that Manaus’s late-summer slowdown in COVID-19 cases had happened, at least in part, because a large proportion of the community’s population had already been exposed to the virus and was now immune. Immunologist Ester Sabino at the University of São Paulo, Brazil, and her colleagues tested more than 6,000 samples from blood banks in Manaus for antibodies to SARS-CoV-2.
“We show that the number of people who got infected was really high — reaching 66% by the end of the first wave,” Sabino says. Her group concluded1 that this large infection rate meant that the number of people who were still vulnerable to the virus was too small to sustain new outbreaks — a phenomenon called herd immunity. Another group in Brazil reached similar conclusions.
Such reports from Manaus, together with comparable arguments about parts of Italy that were hit hard early in the pandemic, helped to embolden proposals to chase herd immunity. The plans suggested letting most of society return to normal, while taking some steps to protect those who are most at risk of severe disease. That would essentially allow the coronavirus to run its course, proponents said.
But epidemiologists have repeatedly smacked down such ideas. “Surrendering to the virus” is not a defensible plan, says Kristian Andersen, an immunologist at the Scripps Research Institute in La Jolla, California. Such an approach would lead to a catastrophic loss of human lives without necessarily speeding up society’s return to normal, he says. “We have never successfully been able to do it before, and it will lead to unacceptable and unnecessary untold human death and suffering.”
Despite widespread critique, the idea keeps popping up among politicians and policymakers in numerous countries, including Sweden, the United Kingdom and the United States. US President Donald Trump spoke positively about it in September, using the malapropism “herd mentality”. And even a few scientists have pushed the agenda. In early October, a libertarian think tank and a small group of scientists released a document called the Great Barrington Declaration. In it, they call for a return to normal life for people at lower risk of severe COVID-19, to allow SARS-CoV-2 to spread to a sufficient level to give herd immunity. People at high risk, such as elderly people, it says, could be protected through measures that are largely unspecified. The writers of the declaration received an audience in the White House, and sparked a counter memorandum from another group of scientists in The Lancet, which called the herd-immunity approach a “dangerous fallacy unsupported by scientific evidence."