New evidence on the effectiveness of lockdown

Lockdowns face masks ineffective

A few weeks back I wrote an article about an observational study published in Lancet that, among other things, looked at whether there was any correlation between stringency of lockdown and the number of people who died of covid. It didn’t find any correlation, which suggests that lockdowns don’t work. That study did have some major limitations however.

First of all, it was observational, based on analysis of statistics, and so can only show patterns (or lack of patterns), not cause and effect, and retrospective, meaning that the researchers based their analysis on existing data that had been produced for other purposes. This is a relatively low quality form of evidence. Second, the follow-up period was short, with data only being gathered until May 1st. It could be argued that this is too short a time period to see an effect of lockdown on mortality.

Now, however, we have some new data that addresses both of these limitations. The first comes in the form of a prospective cohort study that was published in the New England Journal of Medicine. A prospective cohort study is a study in which a group of people are recruited and then followed over time to see what happens to them. This is better than a retrospective study, because there is no way of looking at the end result before you begin, and thereby less scope for “cheating”. It’s not as good as a randomized controlled trial (the gold standard in terms of scientific methodology) because you’re not in control of all the variables, and you don’t have a control group, but it is a big step up from just looking at national statistics and trying to draw conclusions from them.

The study was funded by the US Defence Health Agency and DARPA (the Defence Advanced Research Projects Agency), and the purpose of the study was to see if quarantine rules that had been implemented in the US Marine Corps were effective at preventing spread of covid-19. The intervention involved many different parts, so we’re going to go through it in some detail. The group that was studied was new Marine Corps recruits, who were going through their initial training period.

The new recruits were asked to self-quarantine at home for the two weeks immediately prior to arriving at the base to begin their service in the Marine Corps. When they did arrive, they were placed in a further two week quarantine at a college campus that was being used exclusively for this purpose. During the second quarantine period, the recruits were required to wear face masks at all times except when eating and sleeping, to always be at least six feet apart, and they were prohibited from leaving the campus. They had to wash their hands regularly, and were not allowed access to electronics or other items that might contribute to surface transmission of the virus. Furthermore, they spent most of their time outdoors.

The campus was organized in such a way that all movement was unidirectional, and every building had separate entry and exit points, to keep people from getting too close to each other or bumping in to each other. During their time in campus, recruits only had direct contact with other members of their platoon and their instructors. They were not allowed to interact with any of the on-site support staff (cooks, cleaners, etc).

The recruits lived two to a room, ate together with their platoon in a communal eating area, and used shared bathrooms. They were required to disinfect the bathrooms with bleach between after each visit, and the dining hall was cleaned with bleach in between meals.

All recruits had their temperature taken daily and were asked on a daily basis about symptoms. At any sign of symptoms or a raised temperature, they were put in isolation and not allowed to return to their platoon until a PCR test came back negative.

A total of 1,848 marine recruits were enrolled in the study and the average age of the participants was 19. PCR tests for SARS-CoV-2 were carried out on arrival at the campus, and on days 7 and 14 of the two week on-campus quarantine. Anyone who tested positive at any of these time points was immediately placed in isolation. A further 1,619 recruits declined to participate in the study or were excluded because they were under 18. However, the 1,619 individuals who declined to participate in the study followed the exact same restrictions as the study group, except for the fact that they didn’t have PCR tests taken on arrival or on day 7. They therefore cannot be used as a control group, which is unfortunate.

So, what were the results?

16 out of 1,847 recruits (0,9%) tested positive for SARS-CoV-2 on arrival at the campus. All of them claimed to have quarantined at home for the full two weeks before arrival and had not been exposed to anyone with symptoms during that period. 5 of these 16 individuals had antibodies to covid, and were thus most likely not infectious (antibodies generally develop around two weeks after infection, at which point people usually are no longer infectious). Only one of the 16 had symptoms. All 16 were isolated from the rest of the recruits as soon as their results came back positive (within 48 hours).

On day 7, a new round of PCR testing was carried out and a further 24 recruits had become positive to SARS-CoV-2, of which three were symptomatic. On day 14, a final round of PCR testing was carried out, and 11 more recruits had become positive, of which one was symptomatic.

Overall, 1,9% of participants became PCR positive during the two week period, in spite of all the measures taken to prevent spread, although only four people developed symptomatic covid. It is important to note that the infected people were not spread evenly throughout the platoons. Some platoons had a lot of infections, and others had none.

The researchers followed up by looking at which specific covid strains were present among the recruits, in order to figure out where people became infected, and from whom. Not surprisingly, infection happened within platoons, and more specifically, to a large extent within shared bedrooms. In spite of the fact that different platoons were walking in the same corridors, using the same bathrooms, and eating in the same mess hall, no infection happened across platoons – all infections happened within platoons (with one exception, where two people from different platoons were sharing a bedroom).

Another interesting result from the viral genome mapping is how many people a single infected person could go on to infect, in spite of all the measures in place to prevent spread. In two separate platoons, one person brought the virus in from outside, and spread the infection to eight other individuals within their platoon over the course of the two week period.

In some ways I find this the most interesting result of the whole study. The fact that you can go from a single infected person to nine infected people in one platoon over the course of a two week period, in spite of the use of extraordinarily stringent methods to prevent spread, shows how unbelievably infectious SARS-CoV-2 can be.

What can we conclude from all this?

First of all, it is important to note that this study has one problematic aspect, and that is the use of PCR without some kind of follow-up to confirm that a positive result really is a true positive (for example with a viral culture). A second problem is that there is no control group, so it’s impossible to say what would have happened had there been no lockdown-like restrictions.

That being said, this study clearly shows how effectively the virus spreads even when extremely repressive methods are being used to contain it. In spite of strict physical distancing, rigorous hand and surface hygiene, face masks, PCR based screening, daily symptom checks, and two weeks of quarantine before even arriving at campus, the virus still snuck in and was still able to spread effectively among the recruits. The stringency of the measures that were put in place among the recruits was far more extreme than anything that could be accomplished in a civilian setting. And yet, in two of the platoons, the virus still spread like wildfire.

Having said that, it would have been nice to have had a control group to compare with. Hopefully a proper randomized controlled trial will come out at some point that clarifies the remaining question marks, and gives a more definitive answer to the question of what effect, if any, stringent lockdowns have in terms of stopping the spread of covid-19.

There are three other aspects of this study that I find interesting. The first is that it suggests that pre-symptomatic and asymptomatic spread does happen with covid, since anyone showing the slightest symptoms was immediately isolated, and in spite of this, the virus still spread. And the two individuals who were thought to be the index patients for the two big clusters never developed any symptoms themselves

The second is that it gives further credence to the idea that most people with covid are not very infectious, while a small number of people are “super spreaders”. If we presume that the five people who were both PCR and antibody positive on arrival no longer had active infections, then that means 11 people had active covid infections on arrival at the campus. Two weeks later, an additional 38 people had been infected. Of those, 16 were infected by just two people, which means that the remaining 22 were infected by some combination of the other nine. So, two individuals were clearly far more infectious than the rest.

The third aspect that is interesting is that infection only happened within platoons, not between them. That is in spite of the fact that different platoons were using the same spaces, only at different times. To me this suggests that SARS-CoV-2 doesn’t hang around in the air and maintain the ability to infect people who come in to the same space at a later time point, as some people have been suggesting (one recent Swedish study had found evidence of SARS-CoV-2 in a hospital attic and this led to fear-mongering articles in the Swedish media). Rather, it seems from this study that covid-19 only spreads through close and immediate personal contact.

Next up, we have a study that was recently published in Frontiers in Public Health. The authors received no specific funding for the study and reported no conflicts of interest. Like the Lancet study I wrote about a few weeks back, this was an analysis of global statistics. The difference between this study and the previous one is that this one looked at a lot more countries (every country that had at least 10 covid deaths at the end of August was included, which means that 160 countries were included in total), and looked at a much longer time frame. While the earlier study only gathered data up to May 1st, this one gathered data until the end of August. If lockdowns do affect mortality, there should certainly be a visible effect by that time.

So, what were the results?

The was no correlation between the stringency of lockdown and the number of covid deaths. Strong positive correlations with covid deaths were seen with the proportion of the population that is obese, and with the level of sedentary behavior in the population. In other words, the results are perfectly in line with the earlier study published in Lancet. Other factors that were found to correlate positively with covid mortality were age, proportion of the population with cardiovascular disease, and proportion of the population with cancer.

Two factors that showed a strong negative correlation with covid mortality were the general prevalence of infectious diseases in a population, and the average Gross Domestic Product (GDP). This makes sense to me, since poorer countries have more infectious diseases generally, and they also have younger, less obese populations, that are less likely to succumb to covid if infected.

Two other factors that correlated negatively with covid mortality were average temperature and average level of sunlight. Given that covid seemed to disappear in many countries during the summer, and now seems to have returned in autumn, the virus appears to act in a highly seasonal manner, so it makes sense that these correlations would exist. No correlation was seen, however, between humidity and death rate from covid.

What can we conclude from these two studies?

I would say that these studies strengthen the conclusions from my previous article. Lockdown appears to be largely ineffective. Ensuring good overall population health by encouraging a healthy diet and regular exercise does appear to be effective.

But if it is the case that lockdown is ineffective, how come Sweden had so many more covid deaths than other nordic countries?

That is a topic I will come back to in the near future.

You might also be interested in my article about how deadly covid is, or my article about the accuracy of the covid-19 tests.

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42 thoughts on “New evidence on the effectiveness of lockdown”

    Apparently, there was a control group, and it’s results weren’t worse, further confirming that lockdowns and masks don’t work or make a difference.
    The asymptomatic spreader thesis is challenged if not discarded by the Wuhan study and its testing of 10! million people without a single asymptomatic spreader found.
    The low numbers of infected vs. observed, here and in all the vaccine trials, also raise questions about different testing (CT number) standards in those trials and studies compared to the undertaken mass testings of Western populations, or they suggest that a vaccine isn’t really needed, due to the low number of infected alone!

  2. The vaccine trials, in particular the Oxford one, where all participants are being tested weekly, also confirm that the asymptomatic spread is highly unlikely if not non-existant.

  3. Keep writing Dr. Rushworth. Whether your interpretations are correct or not in the long run is irrelevant. Your patient, transparent logic and painstaking research is important ‘grist’ for the mill. Thank you.

  4. Since there is around 90% false positives from PCR tests already at 40 cycles, and most countries use even more cycles than that, (Sweden use 45), the PCR-test is basically useless, except as a manipulation tool.
    Another quite interesting fact, is that despite all the scaremongering propaganda from msm and politicians ( ”its really, really pitch dark in Sweden regarding covid”) stated by the swedish head of state a few weeks ago, the swedish death toll numbers compared to the previous 5 years, has NOT increased at all during the autum, in fact it has not increased since the end of Maj. (SCB death toll/day in Sweden). There is NO excess deaths for 2020 as a whole, in fact since the end of Maj, it’s below average from previous years, and still all this restrictions, still all this threats and scaremongering. Could it possible has anything to do with big pharma, very profiting vaccins, and
    bribed politicians?

  5. It’s quite clear from everywhere around the world that lockdowns are not effective and quite destructive, so it’s disheartening to see that Sweden, which I thought of as the last sane place on Earth, seems to be going down that path. I know there’s a lot of pressure to lock down because of rising case counts, but I’m wondering why there are not any loud voices, such as yours or Tegnell’s that can expose how many false positives these PCR tests produce, especially when they are being used at many more cycles than they are supposed to be.

  6. Nice article (better than the original which missed the points you were making.

    On the question of whether the lockup worked, I wrote an article today suggesting that lockups fail to work because they don’t change the amount we socialise, just who we socialise with. To some extent this research supports my view, that what really matters is close social contact … and that if we aren’t allowed to do it one way … we find other ways to do the same contact, which has the same R0 (for an uninfected population).

  7. These lockdowns, masks, travel restrictions and on and on are about: How much relinquishing control and loss of freedoms are we willing to absorb? Apparently, quite a bit.. Indeed, easily compliant, so many are. So–a lot of evidence we’ve supplied to the authoritarians on what we’ll put up with.

    Until recently, that is. Now–I sense a growing amount of not the virus–but of at some point, civil disobedience towards what is being forced upon us. There are so many that are seeing their businesses languish and so many to never come back. There are so many that are really missing all their past social interactions (which we’ve now found out how important that is). The list goes on, and in regards to the collateral damage, it will show to be staggering and enormous.

  8. The study shows that the virus spread in the dorms where the soldiers sleep, without masks

    China did very well with lockdown. Results speak for itself.

  9. It is totally foolish to conclude from the furnished information that a second platoon, using the same space, and not being infected proves anything about the virus “hanging around.” Simple tests, such as Millipore filter paper, used with a common holder and readily available hand pumps can assay the viral load in an airspace, and rapidly determine if a ventilation effect exists. Why do all these articles make one believe all the Scientists are retired or dead?

  10. “Two factors that showed a strong negative correlation with covid mortality were the general prevalence of infectious diseases in a population, and the average Gross Domestic Product (GDP). This makes sense to me, since poorer countries have more infectious diseases generally, and they also have younger, less obese populations, that are less likely to succumb to covid if infected.” The negative correlation with GDP is a bit of a puzzle: there was already an obesity and an infectious disease variables in the regression, and there must have been an age one since that is one of the most obvious and well- known correlations. So the negative correlation with GDP can’t be explained by those. Instead it could be an instance of less is more. I wonder if for instance the negative correlation could be explained by better use of scarce medical resources. In a number of rich countries such as the US the pressure to “do something” was so great that medical personnel were put to work without proper PPE and ended up being a major vector of transmission of the virus. Poorer countries are more used to scarcity and would likely take better care of medical personnel, the scarcest of resources. Or more broadly, death and disease are less shocking in poorer countries and so their response has been more rational.

    I am a big fan by the way. I wish there was a doctor with your healthy skepticism near where I live. I am looking forward to your next post

  11. Thanks Sebastian!
    1. Wuhan test results of almost 10 million published in Nature:
    “city-wide SARS-CoV-2 nucleic acid screening programme between May 14 and June 1, 2020 in Wuhan. All city residents aged six years or older were eligible and 9,899,828 (92.9%) participated. No new symptomatic cases and 300 asymptomatic cases (detection rate 0.303/10,000, 95% CI 0.270–0.339/10,000) were identified. There were no positive tests amongst 1,174 close contacts of asymptomatic cases. “

    1. Hi Luke, if they test 10 million people and only get 300 positives, of which all are asymptomatic, then I would think all 300 are false positives, so it’s not strange that they weren’t able to pass on infection.

  12. 2. Collateral effects of Lockdowns and restrictions:
    Note, I have personally lost one relative to covid19 in a care home, but also friends who couldn’t get treatment due to Lockdowns and restrictions.

    Here is a comprehensive resource for mainstream investigative journalism and peer reviewed scientific studies on collateral effects of covid19 response:

    So what is overall mortality in Sweden v neighbouring countries. Do they have higher non covid deaths per 100,000

  13. Sebastian,

    What is your view on the LFT (Lateral Flow Test) compared with PCR – especially in public domain testing mostly healthy/non infected?

    It appears the Army run LFT in Liverpool of over 60,000 including 23,000 children UK indicates PCR over estimated “cases” by 80 % and even then was around 0.7% for what was called in mainstream media the hotspot for infections, ICU shortages…..

  14. This question might seem foolish, but…
    If aerosol isn’t a transmission agent in the most cases (except bedrooms, apparently) and droplets couldn’t travel the 6 feet gap (without cough — couldn’t at all, with masks — even cough couldn’t propel them so far, only about 30-35 cm.), what was the transmission method? Something is missed there, I think, but I may be wrong, of course.

    1. Hi Sergey,
      I think transmission is through droplets and aerosols, but it doesn’t seem like the aerosols stick around in the air very long in a concentration sufficient to cause infection, at least in this study.

  15. Great stuff Simon. We have found that air quality is the important parameter to consider for indoor spread>most of which is now airborne as people are wearing masks. We have businesses open windows where possible, increase air exchange, filter with MERV-13, and cleanse with ionization and/or UV light. Incredible improvement

  16. Hi, Sebastian.
    Thanks for your answer. But that’s a question: if it is droplets, how? They propelled because of cough without masks to about 1.-1.5 meters, right? With masks this distance decreases to 0.3-0.4 meters. But here they had 1.8 meters and masks, so droplets don’t seem to be able to travel this distance. Is it possible that masks collected infectious particles and allow them to be inhaled in quantity, enough for the contagion?
    Considering aerosol, yes, it seems that only if somebody stays in the one room with the spreader during long time (3-8 hours) it becomes the main method of transmission. Outside the bedrooms though that’s not the case.

    First: we can’t trust China’s data.
    Second: China did not impose a national lockdown.

  18. Hi Luke. 300 false positives of 10 million tests amounts to a false positive rate of 0.003%. That would be an extremely accurate test. Reports are that the false positive rate of the PCR test is more in the range of 1%. But even 0.1% (which would be a very good test!) is by a factor of 30 higher. Also, in August, the Swedish Public Health Service reported that they had to correct their data due to too many false positives of the test kits. Those test kits came from BGI Biotechnology of — Wuhan. So in May China makes 10 million tests in 3 weeks with a super-precise test but they ship a super-bad test to Sweden? You are free to believe all this of course. Pretty amazing what gets published in Nature these days… Alternative explanation of what’s going on here: Best wishes to all in this “surreal lockdown territory”…

  19. Sebastian, I don’t think the inference you’re making from the first study is correct.
    First: this study illustrates how transmission can occur. Whatever you want to say, the basic idea of lockdown is that you prevent between household transmission. You won’t prevent within household transmission with a lockdown. A study looking at viral transmission that mainly happens within platoons is kind of a study of intrahousehold transmission. So you can’t say much about interventions to prevent inter-household transmission. Ergo can’t say much about lockdown as a policy from this study. What’s more, the virus didn’t spread “like wildfire”. If 14 day incidence is lower than incidence at day 0 or at day 7, then the effective reproduction number is below 1. A ‘first round’ of growth is entirely explainable by spread from non-participants, missed infections at day 0, and the fact that the entering recruits infect their closest buddies, but then their closest buddies can’t infect them back (saturation).


    Your “argument” that lockdowns “worked” in China is the worst example of cum hoc ergo propter hoc FALLACY I have read today.

  21. 1) Who would sleep with a mask on? 2) China? Seriously? Any information coming out of China is controlled by the Communist Party and should be automatically suspect.

  22. There will be problems with any analysis relying on pcr testing results. The pcr test does not detect actual viruses and therefore cannot determine if a person is infected. Also, if a person is sick and tests positive, the result cannot tell you with certainty the SARS-CoV-2 virus is actually the microbe causing the illness.

    Science should be based on fact, not assumptions. The truth behind the covid pcr test is that it is all based on assumptions.

  23. How does it get around then? I thought the difference between Covid-19 and SARS was the ease of its transmission. And what about the D214G (or was its name the other way round) mutation in the US that spread more easily but wasn’t any more dangerous?

  24. The question is: how do the Chinese contain the virus that effectively?
    My theory is like: they got a PCR test validated to their own standards which tests on at least 6 genetic sequences. Maybe with this procedure, AI & BigData analyses used on PCR tresholds and their population surveillance systems, they can – indeed – identify superspreaders and their infection chains much more efficiently and effectively. The host is the key to control the disease by vaccination or by identifying and isolating the most infectious ones. The latter is – from what I believe – the Chinese do now!

  25. Sebastian
    Am getting reports that Swedens official reporting of deaths is very slow and that the current Covid19 death rate is much higher than the figures would suggest. Any comments?

  26. Are you more concerned with the spread, generally, or with the spread among at-risk individuals? And, basic psychology (and psych warfare) points out how vulnerable humans are to conditioning (in this case as a concomitant variable that lasts much longer than the specific disease itself). Fear as disease that sets-up for a conditioned / trained / cultivated/ facilitated response, obviously more of a concern for survivors, or should be.

    1. I’m not the least bit concerned about spread among the young and healthy, because the risk to them is infinitesimal. And covid is going to be around forever, so the sooner we learn to live with it, the better.

  27. I only wore a face mask once last year and that was to do some sanding! The reason? Because I live in New Zealand and we had a lockdown and it worked. While most of the rest of the world is in turmoil and having a second or third wave we are going about life as usual.

    Our one concession is that we can’t freely come and go from the country but when you live somewhere as beautiful as we do that is no hardship!

  28. There is a misunderstanding common that only positives need to have viral culturing done. That view is incorrect. False negatives in a viral transmission study will miss possible sources of infection. If 20% of the marines had false negatives, then there could be many other sources of infection besides the “index cases.”

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