Study: Shutdowns stopped 60M infections
Shutdown orders prevented about 60 million novel coronavirus infections in the United States and 285 million in China, according to a research study published Monday that examined how stay-at-home orders and other restrictions limited the spread of the contagion.
A separate study from epidemiologists at Imperial College London estimated the shutdowns saved about 3.1 million lives in 11 European countries, including 500,000 in the United Kingdom, and dropped infection rates by an average of 82%, sufficient to drive the contagion well below epidemic levels.
The two reports, published simultaneously Monday in the journal Nature, used completely different methods to reach similar conclusions. They suggest that the aggressive and unprecedented shutdowns, which caused massive economic disruptions and job losses, were effective at halting the exponential spread of the novel coronavirus.
“Without these policies employed, we would have lived through a very different April and May,” said Solomon Hsiang, director of the Global Policy Laboratory at the University of California at Berkeley, and the leader of the research team that surveyed how six countries — China, the United States, France, Italy, Iran and South Korea — responded to the pandemic.
His team estimated that, in the initial days after the virus was seeded in each country, and before the shutdowns, the number of infections was doubling every two days.
“The disease was spreading at a really extraordinary rate that is rare even among very infectious diseases,” he said in an interview. The global response to COVID-19, the disease caused by the virus, resulted in “saving more lives in a shorter period of time than ever before,” he said in a separate conference call with reporters.
The two reports on the effectiveness of the shutdowns come with a clear warning that the pandemic, even if in retreat in some of the places hardest hit, is far from over. The overwhelming majority of people remain susceptible to the virus. Only about 3% to 4% of people in the countries being studied have been infected to date, said Samir Bhatt, senior author of the Imperial College London study.
“This is just the beginning of the epidemic: we’re very far from herd immunity,” Bhatt said Monday in an email. “The risk of a second wave happening if all interventions and precautions are abandoned is very real.”
The Berkeley study used an “econometric”
model to estimate how 1,717 interventions, such as stay-at-home orders, business closings and travel bans, altered the spread of the virus. The researchers looked at infection rates before and after the interventions were imposed. Some of these interventions were local, and some regional or national.
The researchers concluded that the six countries collectively managed to avert 62 million test-confirmed infections. Because most people who are infected never get tested or diagnosed with covid-19, the actual number of cases that were averted is much higher — about 530 million in the six countries, the Berkeley researchers estimated. They estimated that the United States, had it not imposed shutdowns and other measures, would have seen an additional 4.8 million diagnosed infections and 60 million actual infections.