Have COVID-19 Lockdown policies been effective?


Has there been any peer-reviewed research conducted into the effectiveness of the Lockdown policies?

Some might seriously wonder if it has all been for nothing. Most would more reasonably conclude that it has been effective, but would be hard-pressed to put a precise number on it.

If we turn to the scientific literature, there has this week been some new insights.

Nature (Jun 8, 2020) : The effect of large-scale anti-contagion policies on the COVID-19 pandemic

This paper has just become available via Nature’s Accelerated Preview process. To be clear, the paper has passed peer-review, and it has been accepted for publication. What is available is the text that has had preliminary formatting. What still needs to happen is that the text and figures will undergo copyediting and a proof review before the paper is published in its final form.

What did the study researchers do?

Here, we compile new data on 1,717 local, regional, and national non-pharmaceutical interventions deployed in the ongoing pandemic across localities in China, South Korea, Italy, Iran, France, and the United States (US).

[Side Note: They use the term “non-pharmaceutical interventions” to describe what we commonly know as lockdowns and also other policy variations such as school closures]

We then apply reduced-form econometric methods, commonly used to measure the effect of policies on economic growth , to empirically evaluate the effect that these anti-contagion policies have had on the growth rate of infections.

What did they discover?

In the absence of policy actions, we estimate that early infections of COVID-19 exhibit exponential growth rates of roughly 38% per day. We find that anti-contagion policies have significantly and substantially slowed this growth. Some policies have different impacts on different populations, but we obtain consistent evidence that the policy packages now deployed are achieving large, beneficial, and measurable health outcomes.

We estimate that across these six countries, interventions prevented or delayed on the order of 62 million confirmed cases, corresponding to averting roughly 530 million total infections. These findings may help inform whether or when these policies should be deployed, intensified, or lifted, and they can support decision-making in the other 180+ countries where COVID-19 has been reported .

This gives us a rather stark picture of how many infections would have occurred if there had been no lockdown. It does not specifically address the question of how many lives would have been saved. Basically they are sticking to what the data tells them and are not going beyond that.

They do however make this point within the paper …

…our analysis focuses on confirmed infections, but other outcomes, such as hospitalizations or deaths, are also of policy interest. Future work on these outcomes may require additional modeling approaches because they are relatively more context- and state-dependent. Nonetheless, we experimentally implement our approach on the daily growth rate of hospitalizations in France, where hospitalization data is available at the granularity of this study. We find that the total estimated effect of anti-contagion policies on the growth rate of hospitalizations is similar to our estimates for infection growth rates

Is there anything else available?

Actually, yes there is.

Nature (Jun 8, 2020) : Estimating the effects of non-pharmaceutical interventions on COVID-19 in Europe

Yes, same journal and, yes, published same day. Looks like a bit of joined up thinking is happening at Nature.

It is a very similar, but quite independent study.

What did they do?

We study the impact of major interventions across 11 European countries for the period from the start of COVID-19 until the 4thof May 2020 when lockdowns started to be lifted.

Our model calculates backwards from observed deaths to estimate transmission that occurred several weeks prior, allowing for the time lag between infection and death. We use partial pooling of information between countries with both individual and shared effects on the reproduction number. Pooling allows more information to be used, helps overcome data idiosyncrasies, and enables more timely estimates. Our model relies on fixed estimates of some epidemiological parameters such as the infection fatality rate, does not include importation or subnational variation and assumes that changes in the reproduction number are an immediate response to interventions rather than gradual changes in behavior. Amidst the ongoing pandemic, we rely on death data that is incomplete, with systematic biases in reporting, and subject to future consolidation.

What did they find?

We estimate that, for all the countries we consider, current interventions have been sufficient to drive the reproduction number Rt below 1 (probability Rt< 1.0 is 99.9%) and achieve epidemic control. We estimate that, across all 11 countries, between 12 and 15 million individuals have been infected with SARS-CoV-2 up to 4th May, representing between 3.2% and 4.0% of the population.

Our results show that major non-pharmaceutical interventions and lockdown in particular have had a large effect on reducing transmission.

Continued intervention should be considered to keep transmission of SARS-CoV-2 under control.

Lives Saved by the lockdown policies

Clearly the lockdowns have had a profound impact. If we had not done this then the death toll would have been literally millions of people.

“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.

“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 BIG Highlight

Many people were successfully shielded, but the risk remains. There is no vaccine and so there is no going back to business-as-usual, this is far from over.

Only 3.2% to 4% of the population have been exposed, the vast majority have not.

“This is just the beginning of the epidemic: we’re very far from herd immunity, The risk of a second wave happening if all interventions and precautions are abandoned is very real.”

What we do all see is the economic impact. Jobs lost, businesses gone, stores closed forever because they can’t bounce back.

What we don’t see is what might have happened, the literally millions of deaths that have so far been prevented. 

This creates a psychological desire in some minds that leans away from the idea of any further lockdowns. What the studies demonstrate is that lockdowns do work and did work well. The ultimate outcome will however very much depend upon what happens next.

A lockdown is not a solution or a cure, we simply hit pause and bought ourselves some time, we still have the capacity to completely discard that advantage.

Lockdown policy effectiveness – Further Reading

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