Did lockdowns help curb COVID spread? Why some experts doubt controversial new study
A study that suggests “lockdowns” were mostly ineffective at curbing the spread of COVID-19 is capturing the public’s attention — and sparking criticism from some medical experts who have spoken out against its findings.
Among the confusion is the study’s definition of a lockdown and where the study comes from.
It aimed to analyze whether lockdowns reduced COVID-19 deaths and argues they “have had little to no public health effects” in the report shared to Johns Hopkins University’s Krieger School of Arts & Sciences website as a “working paper” that’s not peer reviewed. It wasn’t shared to JHU’s Coronavirus Resource Center or its Department of Epidemiology.
The work, which is a “meta-analysis” of several studies, said that lockdowns caused “enormous economic and social costs” and “are ill-founded and should be rejected as a pandemic policy instrument.”
Some media reports suggest the study comes from JHU itself, but the paper notes “the views expressed in each working paper are those of the authors and not necessarily those of the institutions that the authors are affiliated with.”
The authors are all economists, including Steve H. Hanke, who is the co-director of JHU’s Institute for Applied Economics, Global Health, and the Study of Business Enterprise.
Among the study’s critics is one professor from Imperial College London who said it has “flaws,” mainly because of how a lockdown is defined, and warrants careful interpretation, according to Science Media Centre.
“The authors define lockdown ‘as the imposition of at least one compulsory, non-pharmaceutical intervention’. This would make a mask wearing policy a lockdown,” said Samir Bhatt, a professor of statistics and public health. “For a meta-analysis using a definition that is at odds with the dictionary definition (a state of isolation or restricted access instituted as a security measure) is strange.”
Another Imperial College London professor, Neil Ferguson, noted how lockdown measures differed from country to country and said the report “does not significantly advance our understanding,” according to Science Media Centre.
More on the study
Study authors specifically defined lockdowns as non-pharmaceutical interventions – “any government mandate that directly restrict peoples’ possibilities, such as policies that limit internal movement, close schools and businesses, and ban international travel.”
The work screened 18,590 studies that could “potentially address the belief” about lockdowns reducing COVID-19 deaths, according to authors. After more screening, ultimately “24 qualified for the inclusion in the meta-analysis.”
These studies were divided into three groups, and an analysis of all three “support the conclusion that lockdowns have had little to no effect on COVID-19 mortality,” according to the authors.
The ones analyzed in a “stringency index” category found “lockdowns in Europe and the United States only reduced COVID-19 mortality by 0.2% on average,” according to the work.
Only one of the studies in this category, by Fuller et al. (2021) “found a substantial effect” that lockdowns reduced COVID-19 deaths, researchers acknowledged.
As for the remaining studies separated into the other two categories, study authors wrote they were “ineffective” and found “no broad-based evidence of noticeable effects on COVID-19 mortality.”
More on why experts question the study
“Smoking causes cancer, the earth is round, and ordering people to stay at home (the correct definition of lockdown) decreases disease transmission. None of this is controversial among scientists,” Dr Seth Flaxman, an associate computer science professor at Oxford University, said in a statement, according to Science Media Centre. “A study purporting to prove the opposite is almost certain to be fundamentally flawed.”
The professor points out how much of the eligible studies analyzed in the work are from an economic standpoint, not from an epidemiological standpoint.
Flaxman also notes that the timing of lockdowns compared to COVID-19 deaths is important.
“Later lockdowns are less effective than earlier lockdowns, because many people are already infected,” Flaxman said. “Lockdowns do not immediately save lives, because there’s a lag from infection to death, so to see the effect of lockdowns on Covid deaths we need to wait about two or three weeks.”
Ferguson echoed Flaxman’s point in saying lockdown measures, as defined by the authors, “are intended to reduce contact rates between individuals in a population, so their primary impact, if effective, is on transmission rates.”
“The duration of the intervention needs to be accounted for when assessing its impact,” Ferguson added, according to Science Media Centre.
This story was originally published February 4, 2022 at 3:08 PM with the headline "Did lockdowns help curb COVID spread? Why some experts doubt controversial new study."
.jpg)