For those who don’t know, my day job is medical editing. I am not a medic, but I spend my days putting medical articles into clearer English.
In the past week I've been reading articles about epidemiology, Wuhan, and ventilators.
I work at home anyway, but there’s been a bit of a lull the past couple of days, so I’m taking this opportunity to use my skills to help other people understand some of the important science that is affecting our lives right now. Specifically, I’ve read the epidemiology report that models—attempts to predict statistically—what may or could happen in the COVID-19 pandemic. Believe it or not, understanding some things directly from the report made me feel somewhat better. I thought some people might be interested or even helped by a few plain-English notes I’ve made. (The complete report, from Imperial College London, is at https://www.imperial.ac.uk/mrc-global-infectious-disease-analysis)
Three important “takeaways”: First, this report’s modeling is what is guiding decisions being made in the U.K., the U.S., and elsewhere. (Its models are for Great Britain and the States, but can be applied to other countries.) Many people are understandably anxious and confused about the rapid changes in decision making, or even angry that what officials were saying days or weeks ago has now changed. As I read this report, it seems clear to me that officials are reacting in real time, and that it may be entirely appropriate that policies are changing and will continue to change. That does not mean that no mistakes have been made. It just means that, when advice changes, or when a different state or country is making a different decision from yours, that may be for entirely scientific reasons, and is not necessarily a cause for additional concern.
Second, we can expect at least 18 months of this virus somewhat disrupting our lives. Not 18 months of what we are going through right now, but before the virus recedes into something we don’t think about much anymore, that is part of the manageable world.
And third, none of these models assume 100% compliance. It would be impossible for everyone to adhere to all the guidelines all the time, even if everyone meant well, simply because there is always confusion and people who are less informed. The models assume that any measures taken will be adhered to by 50- 70% of people. It is obvious that the higher the level of cooperation, the better, but the models inevitably include some degree of “give.”
The details
To be sure, the findings of this report are extremely serious. We can tell this by the unprecedented responses around the world. The lead author himself, Neil Ferguson, has been found to be infected with the novel coronavirus. So while I do not think we are served by anxiety, there is no doubt that this is a very serious situation and we must all follow the guidance faithfully, from the health officials where we live.
My notes below are in two parts: 1. What the models show about what scientists expect could happen with this pandemic, and 2. What the different steps we are being instructed to do actually mean. I have made them as concise as possible.
1. What the models show about what scientists expect could happen with this pandemic
There are, broadly, four ways that governments and societies could choose/are choosing to address the pandemic. The first way is to do absolutely nothing and just let it rip. That is clearly not a real option, so let’s focus on the other three. They are: a. containment, b. mitigation, and c. suppression.
There are, broadly, four ways that governments and societies could choose/are choosing to address the pandemic. The first way is to do absolutely nothing and just let it rip. That is clearly not a real option, so let’s focus on the other three. They are: a. containment, b. mitigation, and c. suppression.
1.a. Containment meant keeping the virus totally contained in a limited place, such as a hospital or a cruise ship. To some extent, it has been tried and succeeded in places like South Korea. Containment requires everyone to be checked for symptoms (e.g., temperature), then isolated from others until they can be tested or until the incubation period of the virus is over (7-14 days). It requires widespread testing to be available. It also requires contact tracing—finding, testing and, if necessary, isolating everyone who was also on that same ship, for example.
Containment is the only option that results in actually keeping the virus out of society and, perhaps, never coming back. But this virus turned up in so many places, and in so many of them there was little or no testing equipment, that basically we are past this option now. There is no point in worrying about it anymore (that’s my editorializing).
1.b. Mitigation was, for example, what the U.K. was trying at first. The idea is to keep the impact of the virus limited by focusing on protecting the most vulnerable people (through age or underlying chronic conditions) by isolating them, but otherwise, understanding that the virus would naturally spread through society. When the U.K. government came under a lot of criticism for mentioning “herd immunity,” this was a response to the information they had at the time: an expectation that this epidemic in the U.K. might lead to 20,000 deaths. That is obviously a horrible number, and to many people, it sounded callous to compare this to a “typical” flu year, where 8,000 deaths can be attributed to influenza. But when people were referring to the novel coronavirus as “a bad flu,” this is what they were talking about.
Twenty thousand deaths would represent a really bad flu year. It is also necessary to point out that some of those deaths would always take place, in any year; it is impossible to know how many of them would not have taken place without the flu. But it’s not totally unreasonable, following the mitigation model, to think that doing as much as possible to protect vulnerable people, while letting the infection spread to other people, would result in herd immunity, an ultimate benefit to society. Because since containment failed, at some point this infection is going to come back. It isn’t going to disappear. And if the majority of people had developed some resistance to it, that means that the virus would not continue to be the disaster it is today, but something more manageable, like the flu.
1.c. Suppression is an attempt to suppress the virus as much as possible. That is where the measures we are seeing now come in. It involves assuming everyone is potentially infected, and instructing us all to stay away from each other. It doesn’t do anything about herd immunity or the problem of what happens when these drastic measures are, eventually, lifted. It is just trying to keep the virus suppressed until more testing, treatments, possibly even a vaccine, become available in the future. (Anything we can do to reduce the number of cases makes it more feasible to do widespread testing, tracing of infected people’s contacts, and effectively quarantine.)
What the Imperial College modeling showed, crucially, was that the 20,000 figure was off. It turned out to be, if I may make a comparison, like a model showing Hillary Clinton had a 99% chance of winning the 2016 election, instead of a model showing a 2 out of 3 chance. Both models existed in 2016, but only the latter was reasonable.
The modeling in this report estimated that following the mitigation strategy was not likely to lead to a bad flu year. In Britain, following a mitigation strategy was likely to lead to 250,000 deaths, instead of 20,000. And the reason for this was not that that a quarter of a million people would die of COVID-19; it’s that the health system would be overwhelmed, so many times over, that many other people, who would have gotten sick with other things, would not be able to get the care that they needed. That is what would lead to an intolerable number of deaths.
This has to be avoided and that is why we are seeing suppression measures now. No one wanted these because they are causing such massive economic disruption and hardship, not to mention this is not normal in a liberal democracy. But there is no good alternative.
2. What the different steps we are being instructed to take actually mean
The scariest number many of us are hearing is “18 months to 2 years.” This does NOT mean that suppression, as it is currently being practiced, will or could go on for that length of time. It means the amount of time that we are going to need to deal with this virus as a big problem, while things like better testing regimens, treatments, and perhaps a vaccine are being developed. There are already clinical trials underway so researchers are working as fast as they can. But the “at least 18 months” figure relates not to some guarantee that a vaccine will be available, but a period of time during which different suppression steps may be enforced or relaxed, at different times and in different places. The four steps examined in this report are: case isolation, household quarantine, school and university closure, and general social distancing.
2a. Self isolation and social distancing are both new terms to most of us, but they are not the same thing. Case isolation refers to anyone with the virus, or anyone showing symptoms of COVID-19 (when we aren’t in a position to test everyone), needing to stay home and basically in isolation from everybody, except members of their own household, for 7 days.
2.b. Household quarantine means that everyone in the same household as an infected or symptomatic person stays home for 14 days. This means their contacts with others outside the household are drastically reduced (though, inevitably, not eliminated), while their contacts within the household of course go up.
2.c. School and university closure is just what it says. The assumption of the model is that school would be closed and most, though not all, universities would be closed. Inevitably, contacts of students with members of their own households and community would go up while they are not in school.
2.d. Social distancing is, in the suppression model, advised for the entire population. Everybody’s contacts outside their own household go down (though again, not to zero). At the same time, contacts with their own households go up, because they are now with those people and not at school or work.
Although no one knows when “the peak” or this curve we are trying to flatten is going to happen, the modeling estimates that after the initial period we keep hearing about—3 months—we will at least be in a position to test and monitor how things are going in our communities: how many people actually have the virus, how many cases are in the hospital, etc. If we have these types of data, we can then decide, appropriate to different places or parts of the country, to relax certain measures for a while, bearing in mind we may have to put them in place again. As long as these decisions are based on data, these types of inconsistencies around the country or world may actually be appropriate. We should not panic, but nor should we expect the situation to go away all at once.
In some sense, though, I hope that we don’t ever go back to “normal,” as in, push the reset button for exactly the way our societies were before this virus developed. Such massive disruptions as we are experiencing now could lead to some positive things, besides just dealing with the emergency at hand. We ought to discover some useful things about what wasn’t working in our societies before the virus, and what we can do better. I hope soon to write another blog post about that.
