You said that “In epidemiology it is a basic fact in the 101 textbook that slowing long distance transmission (using quarantines / travel restrictions) is very important.” The parentheses make the statement incorrect. Obviously there are discussions of this, but I just checked my copy of “Modern Infectious Disease Epidemiology: Concepts, Methods, Mathematical Models, and Public Health.” It discusses travel and the contribution to spread, but mostly focuses on the way IHR limits the imposition of travel bans, and why such bans are considered problematic. It does mention quarantines and travel restrictions, but they aren’t the key tools that are recommended.
Also, you said “I would be interested in some justification of the claim that face masks are not very useful.” That isn’t what I said. I said that “mask wearing by itself is only marginally effective.” See this FHI paper, which estimated, albeit with very low confidence, that mask policies were almost entirely ineffective—far more pessimistic than my claim. That is because that paper is likely to be understating the impact, as they admit. It seems clear that maks wearing reduces spread somewhat, but note that this is because of reducing spread from infectious individuals, especially pre-symptomatic and asymptomatic people, not protecting mask wearers. The early skepticism was in part based on the assumption, which in March seemed to have been shared by both promoters and skeptics, that the benefits were that masks were individually protective, rather than that they helped population-level spread reduction. It turns out that (contra the FHI paper,) there seems to be some impact helping spread reduction. Even so, it’s not enough to bring R<1 without other interventions, either closures, or an effective test and trace program, as our forthcoming paper argues. (I will also note that one key thing that is changing from that pre-print version is because reviewers pointed out that we were likely too optimistic in our estimate of mask effectiveness, and the literature supports much smaller impacts.)
EDIT: I notice I am confused about why people downvote comments that make substantive points without replying. If the tone or substance is problematic, I certainly think downvotes are acceptable, but I think the norm is supposed to be that you also tell people what you think they did wrong.
It seems clear that maks wearing reduces spread somewhat, but note that this is because of reducing spread from infectious individuals, especially pre-symptomatic and asymptomatic people, not protecting mask wearers. The early skepticism was in part based on the assumption, which in March seemed to have been shared by both promoters and skeptics, that the benefits were that masks were individually protective, rather than that they helped population-level spread reduction.
The early *arguments* I saw were mainly about whether masks meaningfully reduced the wearer’s chances of getting infected. But it was already conventional wisdom that masks did meaningfully reduce the wearer’s chances of infecting others, people just weren’t taking the next step of arguing for general mask use on these grounds. For example, the early March CDC recommendation (linked in the anti-CDC LW post) was:
CDC does not recommend that people who are well wear a facemask to protect themselves from respiratory diseases, including COVID-19.
Facemasks should be used by people who show symptoms of COVID-19 to help prevent the spread of the disease to others. The use of facemasks is also crucial for health workers and people who are taking care of someone in close settings (at home or in a health care facility).
By mid March, there were organized efforts to increase mask use on the grounds that it reduced the wearer’s chances of infecting others. The Czech government (which mandated mask use on March 19) and the #Masks4All campaign were the most prominent ones that I saw—both encouraged people to make their own cloth masks and used the slogan “My mask protects you, your mask protects me” (they may also have talked about some risk-reduction benefits for the wearer). A quick search turns up this March 14 video (in Czech, with English closed captioning available) as the earliest source I could quickly find clearly making this case for widespread mask use.
Yes—it took me until mid or late March to be fully on board. See my comment here to a post arguing for pushing handwashing instead of suggesting masks, which I changed my mind about in mid to late March.
I know the conversation these days is (rightly) about preventing presymptomatic transmission from the wearer, but I’m personally still at ~80% that masks probably protect the wearer at least a little, though agree that the effect may not be huge.
Obviously there are discussions of this, but I just checked my copy of “Modern Infectious Disease Epidemiology: Concepts, Methods, Mathematical Models, and Public Health.” It discusses travel and the contribution to spread, but mostly focuses on the way IHR limits the imposition of travel bans, and why such bans are considered problematic. It does mention quarantines and travel restrictions, but they aren’t the key tools that are recommended.
Could you expand on what arguments they present?
Background / my current take:
The past year I have been reading a little bit about this received wisdom in epidemiology (Quarantines and travel restrictions do not work! Or people should not do that because they are too costly economically/because of human rights!), and in my view I have downgraded the profession’s scientific credibility accordingly (that is, failing at rationality), as I have had difficulties finding the actual arguments with numbers and models instead of review articles which say this kind of things as conclusive and cite something which does not appear all that conclusice to a sceptical reader (Usually: airport temperature-taking in Asia during SARS did not work, and Spanish flu eventually reached Australia after several months of not spreading there.)
In contrast, going by my understanding of basic maths, it seems foregone conclusion that if one has limited test&trace capability, limiting introduction of new infectious cases will be helpful for the available capacity to contain new clusters. The amount of help depends on parameters of the measures taken and the disease itself, so it does not help always to great effect. NZ provides a plausible example that it was a helpful move for containing this particular disease. Likewise IIRC WHO and similar bodies have apparently pledges and such not to implement travel restrictions, and such universal policy decisions scream “ideological” to me. The cost-benefit calculus on these matters is not for some group of academians to dictate anyway. Nor its their job to state what is politically impossible or possible. Yeah, right, surprisingly many things become politically possible this year. (Such things happen infrequently, but they do happen.)
Other mind-boggling decisions by epidemiological elite here in Finland (that influence my position here) include the conclusion that “if we think clusters have become an uncontrolled epidemic, we will just cease all tracing and other similar efforts”, and “we have this mathematical DE model where we assume we know exactly all the parameters. So if all restrictions influencing R are removed in November, it proves that we will have horribly deadly second wave in November/December unless we actually help the disease a little bit to spread in this R range, for herd immunity you see, trust me we are epidemiologists” (publicized in newspapers, “scientists say that we have horrible second wave in November if we stop the virus too well”). Presumably similar reasoning resulted in our central government department on at least one occasion outright forbidding some regional authorities from testing incoming travellers from Italy at the very moment the test personnel to was going to the airport and they had made media statement starting testing.
First, in that comment, I wasn’t arguing that quarantines aren’t helpful. I said that the parentheses make the claim false; “In epidemiology it is a basic fact in the 101 textbook that slowing long distance transmission (using quarantines / travel restrictions) is very important.” You seem to agree that this is the received wisdom.
And I agree that we should have done border closures earlier, but I would note that the simple counterfactual world, where people in general ignore epidemiologists more often, is far worse than our world in many ways. I think a world where border closures could be done at the drop of a hat would be worse in other ways as well. You can argue, correctly, that only doing closures when actually necessary is better, but I don’t think breaking down the norm of not banning travel would be a net benefit. (See: Chesterton’s fence, and for a concrete example, see China’s ongoing internal and external travel restrictions, and how that enables concentration camps in Xinjian.)
In my view I have downgraded the profession’s scientific credibility
I agree with you that the current failure should make your downgrade your opinion of experts somewhat. But see above about what I think of ignoring epidemiologists more often in general.
“it seems foregone conclusion that if one has limited test&trace capability, limiting introduction of new infectious cases will be helpful for the available capacity to contain new clusters”
Agreed, but there was no reason to have limited test and trace resources. More recent articles confirm that we could have done symptomatic tracing—loss of smell, coughing, etc—and isolation of just those cases, and shut down transmission completely without any testing. Shutting down borders helps, especially without sufficient tests, but it should not have been needed.
“Other mind-boggling decisions by epidemiological elite here in Finland...”
I can’t comment on Finland specifically, but think that your local elite was probably less unanimous at the time, and the international consensus was different as well.
“if we think clusters have become an uncontrolled epidemic, we will just cease all tracing and other similar efforts”,”
Yes, if spread grows too large, tracing + quarantines is in fact not worthwhile, and shutdowns will be cheaper. (You can play with a basic DE model and put costs on tracing to convince yourself why this is true.)
And yes, removing all restrictions does lead to a rebound and worse spread later. Just look at the US.
Yes, if spread grows too large, tracing + quarantines is in fact not worthwhile, and shutdowns will be cheaper. (You can play with a basic DE model and put costs on tracing to convince yourself why this is true.)
Yeah, I tried to imply the problem was in my eyes the flimsy evidence they had a correctly specified model for making that decision. In reality, they didn’t stop tracing at any point (I am not sure but looking at news, the public pressure supported by non-epi computationally oriented scientists might have helped. I hope they will do proper post-mortem afterwards.)
Otherwise, I think point by point response is not necessary. I would stress that I have downgraded my evaluation of epidemiology to the extent that instead merely trusting that “this is what epidemiology profs or textbooks say”, one should review the actual arguments and evidence
You said that “In epidemiology it is a basic fact in the 101 textbook that slowing long distance transmission (using quarantines / travel restrictions) is very important.” The parentheses make the statement incorrect. Obviously there are discussions of this, but I just checked my copy of “Modern Infectious Disease Epidemiology: Concepts, Methods, Mathematical Models, and Public Health.” It discusses travel and the contribution to spread, but mostly focuses on the way IHR limits the imposition of travel bans, and why such bans are considered problematic. It does mention quarantines and travel restrictions, but they aren’t the key tools that are recommended.
Also, you said “I would be interested in some justification of the claim that face masks are not very useful.” That isn’t what I said. I said that “mask wearing by itself is only marginally effective.” See this FHI paper, which estimated, albeit with very low confidence, that mask policies were almost entirely ineffective—far more pessimistic than my claim. That is because that paper is likely to be understating the impact, as they admit. It seems clear that maks wearing reduces spread somewhat, but note that this is because of reducing spread from infectious individuals, especially pre-symptomatic and asymptomatic people, not protecting mask wearers. The early skepticism was in part based on the assumption, which in March seemed to have been shared by both promoters and skeptics, that the benefits were that masks were individually protective, rather than that they helped population-level spread reduction. It turns out that (contra the FHI paper,) there seems to be some impact helping spread reduction. Even so, it’s not enough to bring R<1 without other interventions, either closures, or an effective test and trace program, as our forthcoming paper argues. (I will also note that one key thing that is changing from that pre-print version is because reviewers pointed out that we were likely too optimistic in our estimate of mask effectiveness, and the literature supports much smaller impacts.)
EDIT: I notice I am confused about why people downvote comments that make substantive points without replying. If the tone or substance is problematic, I certainly think downvotes are acceptable, but I think the norm is supposed to be that you also tell people what you think they did wrong.
The early *arguments* I saw were mainly about whether masks meaningfully reduced the wearer’s chances of getting infected. But it was already conventional wisdom that masks did meaningfully reduce the wearer’s chances of infecting others, people just weren’t taking the next step of arguing for general mask use on these grounds. For example, the early March CDC recommendation (linked in the anti-CDC LW post) was:
By mid March, there were organized efforts to increase mask use on the grounds that it reduced the wearer’s chances of infecting others. The Czech government (which mandated mask use on March 19) and the #Masks4All campaign were the most prominent ones that I saw—both encouraged people to make their own cloth masks and used the slogan “My mask protects you, your mask protects me” (they may also have talked about some risk-reduction benefits for the wearer). A quick search turns up this March 14 video (in Czech, with English closed captioning available) as the earliest source I could quickly find clearly making this case for widespread mask use.
Yes—it took me until mid or late March to be fully on board. See my comment here to a post arguing for pushing handwashing instead of suggesting masks, which I changed my mind about in mid to late March.
I know the conversation these days is (rightly) about preventing presymptomatic transmission from the wearer, but I’m personally still at ~80% that masks probably protect the wearer at least a little, though agree that the effect may not be huge.
Agreed—but **for protecting the wearer alone**, I’d say that 10% more handwashing by most people would easily beat 50% more mask wearing.
In further retrospect, this was very, very incorrect.
Could you expand on what arguments they present?
Background / my current take:
The past year I have been reading a little bit about this received wisdom in epidemiology (Quarantines and travel restrictions do not work! Or people should not do that because they are too costly economically/because of human rights!), and in my view I have downgraded the profession’s scientific credibility accordingly (that is, failing at rationality), as I have had difficulties finding the actual arguments with numbers and models instead of review articles which say this kind of things as conclusive and cite something which does not appear all that conclusice to a sceptical reader (Usually: airport temperature-taking in Asia during SARS did not work, and Spanish flu eventually reached Australia after several months of not spreading there.)
In contrast, going by my understanding of basic maths, it seems foregone conclusion that if one has limited test&trace capability, limiting introduction of new infectious cases will be helpful for the available capacity to contain new clusters. The amount of help depends on parameters of the measures taken and the disease itself, so it does not help always to great effect. NZ provides a plausible example that it was a helpful move for containing this particular disease. Likewise IIRC WHO and similar bodies have apparently pledges and such not to implement travel restrictions, and such universal policy decisions scream “ideological” to me. The cost-benefit calculus on these matters is not for some group of academians to dictate anyway. Nor its their job to state what is politically impossible or possible. Yeah, right, surprisingly many things become politically possible this year. (Such things happen infrequently, but they do happen.)
Other mind-boggling decisions by epidemiological elite here in Finland (that influence my position here) include the conclusion that “if we think clusters have become an uncontrolled epidemic, we will just cease all tracing and other similar efforts”, and “we have this mathematical DE model where we assume we know exactly all the parameters. So if all restrictions influencing R are removed in November, it proves that we will have horribly deadly second wave in November/December unless we actually help the disease a little bit to spread in this R range, for herd immunity you see, trust me we are epidemiologists” (publicized in newspapers, “scientists say that we have horrible second wave in November if we stop the virus too well”). Presumably similar reasoning resulted in our central government department on at least one occasion outright forbidding some regional authorities from testing incoming travellers from Italy at the very moment the test personnel to was going to the airport and they had made media statement starting testing.
edit. Clarification
First, in that comment, I wasn’t arguing that quarantines aren’t helpful. I said that the parentheses make the claim false; “In epidemiology it is a basic fact in the 101 textbook that slowing long distance transmission (using quarantines / travel restrictions) is very important.” You seem to agree that this is the received wisdom.
And I agree that we should have done border closures earlier, but I would note that the simple counterfactual world, where people in general ignore epidemiologists more often, is far worse than our world in many ways. I think a world where border closures could be done at the drop of a hat would be worse in other ways as well. You can argue, correctly, that only doing closures when actually necessary is better, but I don’t think breaking down the norm of not banning travel would be a net benefit. (See: Chesterton’s fence, and for a concrete example, see China’s ongoing internal and external travel restrictions, and how that enables concentration camps in Xinjian.)
I agree with you that the current failure should make your downgrade your opinion of experts somewhat. But see above about what I think of ignoring epidemiologists more often in general.
Agreed, but there was no reason to have limited test and trace resources. More recent articles confirm that we could have done symptomatic tracing—loss of smell, coughing, etc—and isolation of just those cases, and shut down transmission completely without any testing. Shutting down borders helps, especially without sufficient tests, but it should not have been needed.
I can’t comment on Finland specifically, but think that your local elite was probably less unanimous at the time, and the international consensus was different as well.
Yes, if spread grows too large, tracing + quarantines is in fact not worthwhile, and shutdowns will be cheaper. (You can play with a basic DE model and put costs on tracing to convince yourself why this is true.)
And yes, removing all restrictions does lead to a rebound and worse spread later. Just look at the US.
Yeah, I tried to imply the problem was in my eyes the flimsy evidence they had a correctly specified model for making that decision. In reality, they didn’t stop tracing at any point (I am not sure but looking at news, the public pressure supported by non-epi computationally oriented scientists might have helped. I hope they will do proper post-mortem afterwards.)
Otherwise, I think point by point response is not necessary. I would stress that I have downgraded my evaluation of epidemiology to the extent that instead merely trusting that “this is what epidemiology profs or textbooks say”, one should review the actual arguments and evidence