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Public Health Policies Have Prevented Hundreds of Millions of Coronavirus Infections

Posted on by Dr. Francis Collins

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Credit: Stock photo/Juanmonino

The alarming spread of coronavirus disease 2019 (COVID-19) last winter presented a profound threat to nations around the world. Many government leaders responded by shutting down all non-essential activities, implementing policies that public health officials were hopeful could slow the highly infectious SARS-CoV-2, the novel coronavirus that causes COVID-19.

But the shutdown has come at a heavy cost for the U.S. and global economies. It’s also taken a heavy personal toll on many of us, disrupting our daily routines—getting children off to school, commuting to the office or lab, getting together with friends and family, meeting face to face to plan projects, eating out, going to the gym—and causing lots of uncertainty and frustration.

As difficult as the shutdowns have been, new research shows that without these public health measures, things would have been much, much worse. According to a study published recently in Nature [1], the implementation of containment and mitigation strategies across the globe prevented or delayed about 530 million coronavirus infections across six countries—China, South Korea, Iran, Italy, France, and the United States. Take a moment to absorb that number—530 million. Right now, there are 8.8 million cases documented across the globe.

Estimates of the benefits of anti-contagion policies have drawn from epidemiological models that simulate the spread of COVID-19 in various ways, depending on assumptions built into each model. But models are sophisticated ways of guessing. Back when decisions about staying at home had to be made, no one knew for sure if, or how well, such approaches to limit physical contact would work. What’s more, the only real historical precedent was the 1918 Spanish flu pandemic in a very different, much-less interconnected world.

That made it essential to evaluate the pros and cons of these public health strategies within a society. As many people have rightfully asked: are the health benefits really worth the pain?

Recognizing a pressing need to answer this question, an international team of scientists dropped everything that they were doing to find out. Led by Solomon Hsiang, director of the University of California, Berkeley’s Global Policy Laboratory and Chancellor’s Professor at the Goldman School of Public Policy, a research group of 15 researchers from China, France, South Korea, New Zealand, Singapore, and the United States evaluated 1,717 policies implemented in all six countries between January 2020, when the virus began its global rise, and April 6, 2020.

The team relied on econometric methods that use statistics and math to uncover meaningful patterns hiding in mountains of data. As the name implies, these techniques are used routinely by economists to understand, in a before-and-after way, how certain events affect economic growth.

In this look-back study, scientists compare observations before and after an event they couldn’t control, such as a natural disaster or disease outbreak. In the case of COVID-19, these researchers compared public health datasets in multiple localities (e.g., states or cities) within each of the six countries before and several weeks after lockdowns. For each data sample from a given locality, the time period right before a policy deployment was the experimental “control” for the same locality several weeks after it received one or more shutdown policy “treatments.”

Hsiang and his colleagues measured the effects of all the different policies put into place at local, regional, and national levels. These included travel restrictions, business and school closures, shelter-in-place orders, and other actions that didn’t involve any type of medical treatment for COVID-19.

Because SARS-CoV-2 is a new virus, the researchers knew that early in the pandemic, everyone was susceptible, and the outbreak would grow exponentially. The scientists could then use a statistical method designed to estimate how the daily growth rate of infections changed over time within a location after different combinations of large-scale policies were put into place.

The result? Early in the pandemic, coronavirus infection rates grew 38 percent each day, on average, across the six countries: translating to a two-day doubling time. Applying all policies at once slowed the daily COVID-19 infection rate by 31 percentage points! Policies having the clearest benefit were business closures and lockdowns, whereas travel restrictions and bans on social gatherings had mixed results. Without more data, the analysis can’t specify why, but the way different countries enacted those policies might be one reason.

As we continue to try to understand and thwart this new virus and its damage to so many aspects of our personal and professional lives, these new findings add context, comfort, and guidance about the present circumstances. They tell us that individual sacrifices from staying home and canceled events contributed collectively to a huge, positive impact on the world.

Now, as various communities start cautiously to open up, we should continue to practice social distancing, mask wearing, and handwashing. This is not the time to say that the risk has passed. We are all tired of the virus and its consequences for our personal lives, but the virus doesn’t care. It’s still out there. Stay safe, everyone!


[1] The effect of large-scale anti-contagion policies on the COVID-19 pandemic. Hsiang S, Allen D, Annan-Phan S, et al. Nature. 2020 June 8 [published online ahead of print].


Coronavirus (NIH)

Global Policy Lab: Effect of Anti-Contagion Policies (University of California, Berkeley)

Video: How much have policies to slow COVID-19 worked? (UC Berkeley)

Hsiang Lab (UC Berkeley)

Global Policy Lab Rallies for COVID-19 Research,” COVID-19 News, Goldman School of Public Policy, June 5, 2020.


  • Elizabeth Davis says:

    Thank you Dr. Collins for continuing to tell it like it is…..

  • AD says:

    Thank you for the explanation, Dr. Collins, your article is always waiting for me.

  • tina says:

    It’s still out there and will continue to be out there…that is how viruses work…they don’t magically disappear because we lock down and ruin people’s lives by shutting down their business or by wearing ineffective masks…this is all ridiculous! Let the virus run it’s course this is how we have to beat it…be strong and let our immune system do it’s job! Not masking up or shutting down.

  • harpat949 says:

    Why is the NIH not addressing the major infection route of airborne coronavirus spread. Countries with predominantly natural ventilation have much lower infection rates than those with closed ventilation systems. Vietnam has a mind boggling 1800 times lower infection rates and zero deaths. I think western experts have bungled it and attributed the low rates to bogus explanations like low rates of testing. If you have zero deaths, testing is immaterial. Besides, only about 5% of the population has been tested.

  • Michael Isaac Lerman says:

    “Hundreds of Millions”? probably a mistake?

    • Moderator says:

      According to the authors, the strategies prevented or delayed about 530 million coronavirus infections in six countries.

      • Pege J Godfrey says:

        That is based on theory, models and statistics. All of which can be completely adjusted by changing a variable in the mathematical equation. We’re in the latter part of July. How many models have been presented? Too many to count. Most of which contradicted another. No one knows who to believe.

  • harpat949 says:

    I would say the strategy caused half a million or so infections and more to come. Only Vietnam seems to know what to do and they have no deaths.

  • Deborah Ericson says:

    In time, the masks will be shown to have little prevention and studies most likely will demonstrate they by their natural fibers actually attenuate an environment to grow virus and other bacteria. Respiration is meant to be expired and contained does not prevent viral hosting. The masks appear to be a psychological tool to give a false sense of security. In reality, social distancing and hand washing by the physics is both to mechanical prevention. The simple mechanics of vigorous sudsing has had little promotion to the public and education to how effective it is in destroying viruses. The public health messages have lacked education how viruses spread by using actual visual demonstrations of what droplets look like around infected persons and how they are spread person to person. And little public affairs messages to good community nutrition to encourage foods high in zinc,Vitamin C and D. Historically, lack of more than adequate ventilation has shown to be a major contributor to the spread of virulent bacteria and virus. The public can handle more education than they have been given credit.

    • harpat949 says:

      It is the lack of adequate ventilation that seems to be the major factor for the high infection rates in the developed world. The third world is lucky they cannot afford HVAC so most of their shopping and living facilities are open ventilation. The third world infection rates are orders of magnitudes lower than the developed countries and our experts are totally blindsided by frivolous technologies. Most of the third world does not know the benefit they have of open ventilation else their remaining infections would almost vanish. The exception is Vietnam. They have focused on the open ventilation concept and achieved zero deaths. They do enforce social distancing vigorously but it is the open ventilation that has prevented deaths and their infection rates are about 2000 times lower than the USA’s. The perverted Western media criticizes the Vietnam government for enforcing the social distancing using police. The prevention of deaths and misery has no value to the western journalists if police is involved.
      I guess the police brutality that occurs every now and then has colored their judgements. One other problem seems to be the profit motive of capitalism prevents thinking of simple low cost solutions and promotes multi billion dollar pharma solutions. The association of HVAC manufactures admit the virus can be spread by HVAC but they don’t recommend turning it off because of loss of comfort but of course the loss of HVAC business must be on their minds.

    • Pege J Godfrey says:

      You’re right, but not because in time, but because the studies have already been done. Research shows that the available masks to the general public will not prevent C19 from penetrating through the materials. They will stop the droplet, but the droplet is just the medium the virus is contained in. The virus is an aersol and will go through the mask and become airborn. Some studies were done pre-COVID using SARS as one of the viruses based on its size as its about the same as C19. Most masks will only catch molecules .3 microns and larger. SARS and SARS-CoV2 are way smaller. So, the masks are helping everyone from spitting everywhere, but the study says that’s about it.

  • James says:

    I was impressed by the use of ‘shutdowns’ and ‘staying at home’ but then halfway through the article switched to ‘lockdowns’, which is unscientific terminology. USA prison jargon doesn’t help with people’s coping mechanisms so please do avoid it.

  • K.S. says:

    I stayed in south korea for long time. South korea has amazing technology to fight against corona virus. thanx for this great article …

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