Tue 3 Nov 2020: Lockdown 2: Revenge Of The Son Of Lockdown: The Sequel

I’m disappointed that the government is going to push us all back into staying at home as of Thursday this week and not allow people to have a life. Just when businesses were breathing a huge sigh of relief and beginning to get back to profitable trading, when theatres and the like were beginning to re-open having spent large sums on re-configuring their premises and on rehearsals … they’re being forced to close again, and for no good reason that I can see. As I wrote a couple of weeks ago, there is no evidence that has been shown to the public that they are the cause of the current resurgence of the lurgi. The pesky pestilence came roaring back when the schools opened and especially when undergraduates went to universities. Those are where the problem obviously lies. Those are what need dealing with. Or if the government is privy to information to the contrary they should share it. Absent that public information we have to assume that they are choosing to inflict misery on normal people, and to hammer what would be some of our sources of pleasure once this is all over, for reasons other than plague prevention. Perhaps that reason is that they have information showing how important it is to keep schools and universities open and that they just can’t be operated safely (I made some suggestions a couple of weeks ago) but again, they’re not sharing that information so that the rest of us can see that they are correct.

I fear that without the media, opposition parties and refusenik Conservatives pointing out the government’s apparent error they’ll get away with it. Alas, the Labour party is too busy being self-congratulatory and saying “you’re just doing what we said you should do weeks ago”, scoring points while being just as wrong as the government. I’m afraid that the government won’t be made to change tack in parliament, nor will the people make their voices heard.

But it’s not all gloom. There is also some good news coming from Liverpool, where regular fast city-wide testing is supposedly going to be piloted.

That news story touches on some of the problems. First, the false positive rate of about 0.1% means that if you are tested every two weeks for six months then about one in thirty people will get at least one false positive at some point during that period. And if the false positive rate is as high as 1% then it’s one in three. That is said to be high enough that the risk of having to isolate and not work for a fortnight will put people off being tested. There are two obvious mitigations. First, if someone tests positive using the fancy new one hour tests, quickly re-test them to make sure. Again assuming a 0.1% false positive rate, the chance of any one person failing that double test at least once in the period goes from 1 in 30 to 1 in 30,000. That sort of re-testing already being done in professional sports that are regularly testing players. Second, the Chancellor has already shown that he’s willing to fling money at people who can’t work because of the lurgi in some circumstances. This is just another such circumstance.

There was also, in an earlier version of that article, mention of people not taking the time off work to get tested. Not sure why that’s a problem given that part of the plan is to have testing in workplaces. Obviously any workplace that refuses to allow testing should just be shut down until they change their mind, just like you would shut down a business that flouted public health regs in other ways such as a rat-infested kitchen. And for smaller workplaces (the vast majority, and where most people work) mobile testing stations that can, for example, park on a street and have people pop into all the shops to take samples, would do the trick.

What the article doesn’t seem to talk about, however, is the false negative rate of these new tests. Where false positives incorrectly say “this person has the lurgi, burn everything he has touched in cleansing fire”, false negatives incorrectly say “this person is disease free, you may lick his weeping disease-ridden sores with impunity”. Turns out that the false negative rate could be as high as 1 in 3, missing a third of infected people. I don’t know if this is a problem though. If you take two thirds of infected people out of circulation at any one time, that would seem to have a huge effect.

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