Covid-19 Prevalence in Karnataka

Finally, many months after other Indian states had conducted a similar exercise, Karnataka released the results of its first “covid-19 sero survey” earlier this week. The headline number being put out is that about 27% of the state has already suffered from the infection, and has antibodies to show for it. From the press release:

Out of 7.07 crore estimated populationin Karnataka, the study estimates that 1.93 crore (27.3%) of the people are either currently infected or already had the infection in the past, as of 16 September 2020.

To put that number in context, as of 16th September, there were a total of 485,000 confirmed cases in Karnataka (official statistics via covid19india.org), and 7536 people had died of the disease in the state.

It had long been estimated that official numbers of covid-19 cases are off by a factor of 10 or 20 – that the actual number of people who have got the disease is actually 10 to 20 times the official number. The serosurvey, assuming it has been done properly, suggests that the factor (as of September) is 40!

If the ratio has continued to hold (and the survey accurate), nearly one in two people in Karnataka have already got the disease! (as of today, there are 839,000 known cases in Karnataka)

Of course, there are regional variations, though I should mention that the smaller the region you take, the less accurate the survey will be (smaller sample size and all that). In Bangalore Urban, for example, the survey estimates that 30% of the population had been infected by mid-September. If the ratio holds, we see that nearly 60% of the population in the city has already got the disease.

The official statistics (separate from the survey) also suggest that the disease has peaked in Karnataka. In fact, it seems to have peaked right around the time the survey was being conducted, in September. In September, it was common to see 7000-1000 new cases confirmed in Karnataka each day. That number has come down to about 3000 per day now.

Now, there are a few questions we need to answer. Firstly – is this factor of 40 (actual cases to known cases) feasible? Based on this data point, it makes sense:

In May, when Karnataka had a very small number of “native cases” and was aggressively testing everyone who had returned to the state from elsewhere, a staggering 93% of currently active cases were asymptomatic. In other words, only 1 in 14 people who was affected was showing any sign of symptoms.

Then, as I might have remarked on Twitter a few times, compulsory quarantining or hospitalisation (which was in force until July IIRC) has been a strong disincentive to people from seeking medical help or getting tested. This has meant that people get themselves tested only when the symptoms are really clear, or when they need attention. The downside of this, of course, has been that many people have got themselves tested too late for help. One statistic I remember is that about 33% of people who died of covid-19 in hospitals died within 24 hours of hospitalisation.

So if only one in 14 show any symptoms, and only those with relatively serious symptoms (or with close relatives who have serious symptoms) get themselves tested, this undercount by a factor of 40 can make sense.

Then – does the survey makes sense? Is 15000 samples big enough for a state of 70 million? For starters, the population of the state doesn’t matter. Rudimentary statistics (I always go to this presentation by Rajeeva Karandikar of CMI)  tells us that the size of the population doesn’t matter. As long as the sample has been chosen randomly, all that matters for the accuracy of the survey is the size of the sample. And for a binary decision (infected / not), 15000 is good enough as long as the sample has been random.

And that is where the survey raises questions – the survey has used an equal number of low risk, high risk and medium risk samples. “High risk” have been defined as people with comorbidities. Moderate risk are people who interact a lot with a lot of people (shopkeepers, healthcare workers, etc.). Both seem fine. It’s the “low risk” that seems suspect, where they have included pregnant women and attendants of outpatient patients in hospitals.

I have a few concerns – are the “low risk” low risk enough? Doesn’t the fact that you have accompanied someone to hospital, or  gone to hospital yourself (because you are pregnant), make you higher than average risk? And then – there are an equal number of low risk, medium risk and high risk people in the sample and there doesn’t seem to be any re-weighting. This suggests to me that the medium and high risk people have been overrepresented in the sample.

Finally, the press release says:

We excluded those already diagnosed with SARS-CoV2 infection, unwilling to provide a sample for the test, or did not agree to provide informed consent

I wonder if this sort of exclusion doesn’t result in a bias in itself.

Putting all this together – that there are qual samples of low, medium and high risk, that the “low risk” sample itself contains people of higher than normal risk, and that people who have refused to participate in the survey have been excluded – I sense that the total prevalence of covid-19 in Karnataka is likely to be overstated. By what factor, it is impossible to say. Maybe our original guess that the incidence of the disease is about 20 times the number of known cases is still valid? We will never know.

Nevertheless, we can be confident that a large section of the state (may not be 50%, but maybe 40%?) has already been infected with covid-19 and unless the ongoing festive season plays havoc, the number of cases is likely to continue dipping.

However, this is no reason to be complacent. I think Nitin Pai is  bang on here.

And I know a lot of people who have been aggressively social distancing (not even meeting people who have domestic help coming home, etc.). It is important that when they do relax, they do so in a graded manner.

Wear masks. Avoid crowded closed places. If you are going to get covid-19 anyway (and many of us have already got it, whether we know it or not), it is significantly better for you that you get a small viral load of it.

Anxiety and computer viruses

I think, and hope, that I’ve been cured of anxiety, which I was probably suffering from for over six years. It was a case of Murphy’s Law taken to its extreme. If anything can go wrong, it will, states the law, and in those six or seven years, I would subconsciously search for things that could possibly go wrong, and then worry about them. And worry about them so much that I would get paranoid.

Let me give you an example. Back in 2008, after a four-month spell of unemployment, I had signed up with a startup. Two days after I signed, which was three weeks before I was going to start work, I started worrying about the health of the startup founder, and what would happen to my career in case he happened to croak between then and my joining the company! It had been a major effort on my part to try and get back to finance, and that job was extremely important to me from a career signaling standpoint (it played a major role in my joining Goldman Sachs, subsequently, I think). So I started getting worried that if for some reason the founder died before I joined, that signaling wouldn’t happen! I worried about it for three days and broke my head about it, until sanity reigned.

This wasn’t a one-off. I would take ages to reply to emails because I would be paranoid that I had said something inappropriate. When I landed in Venice on vacation last year, my office blackberry didn’t get connected for an hour or so, and I thought that was because they had fired me while I was on vacation. It would be similar when I would look at my blackberry first thing in the morning after I woke up, and found no mails. I needed no real reason to worry about something. It was crazy.

When a virus attacks your computer, one of the ways in which it slows down the computer is by running “background processes”. These processes run in the background, independent of what you intend to do, but nevertheless take up so much of your computing power that it becomes extremely hard to function. Anxiety works pretty much the same way. Because there is always so much going on in your mind (most of it unintended, of course), a lot of your brain’s “computing power” is taken up in processing those unwanted thoughts (the brain, unfortunately, has no way of figuring out that those thoughts are unintended). And that leaves you with so much lesser mindspace to do what you want to do.

So you stop functioning. You stop being able to do as much as you were able to. Initially you don’t recognize this, until you bite of more than you could possibly chew a number of times in succession. And then, having failed to deliver on so many occasions, you lose confidence. And lesser confidence means more worry. Which means more background process. And means diminished mental ability. Things can spiral out of hand way too quickly.

I’ve been on anxiety medication for over seven months now, and the only times when I realize how bad things were are when I happen to miss a dose or two, and there is relapse. And having been through it, trust me, it is quite bad.

On the positive side, the impact a well-guided medication process (administered by an expert psychiatrist) can have on anxiety is also tremendous. For the six years I suffered, I had no clue that I was under a cloud of a clinically treatable condition. I didn’t know that it was only a virus that had attacked my CPU, which could be got rid off with sustained dosage of anti-virus, and I had instead thought my CPU itself was slowing down, maybe rusting (at the ripe old age of late twenties). After I started responding to my medication, I was delirious with happiness, with the realization that I hadn’t become dumb, after all.

It was sometime in March or April, I think, when I realized that my medication had come into effect, thus freeing up so much mind space, and I started feeling smart again. When I met the psychiatrist next, I told her, “I feel exactly the way I felt back in 2005 once again!”.

Working for money

One of these days during lunch at office, we had a fairly heated discussion about why people work. One guy and I were of the opinion that the primary reason people work is for money, and everything else is secondary. The third guy, who among the three of us perhaps works the hardest, argued that “people who make a difference” never work for money, and that it is only “ordinary people”, who have no desire to “make a difference” that work for money. He took the examples of people like Steve Jobs and a few famous scientists to make his point.

Now, while I agree that money is the primary reason I work, and which is what I argued that day during lunch, I disagree that the end-of-month salary credit tells the whole story. The way I see it, you need to take a longer-term view of things. So while the short-term money you make is important, and affects important decisions such as quality of short-term life, a more important thing is sustainable returns. While you do your work and get that end-of-month salary credit to bolster your bank account, an important thing is about how much the work you’re doing now will contribute to your income later on in life.

Digression 1: I keep oscillating between wanting to retire at forty and wanting to retire at sixty. And I must admit I haven’t frankly decided which one is more suitable for me. This analysis is more relevant with the retirement at sixty model (which is what I think I’ll end up following, health etc permitting). End of Digression 1.

Digression 2: Not so long ago, some people in my firm wanted to recruit “software engineers from IIT with two to three years of work experience”. Being one of the “CS guys” around, I interviewed quite a few people for that role. Their CVs indicated that had we “caught them” on campus, they would have been sure hires. But two years at a software services shop, I figured in all cases, had made them “rusty”. Spending all their time in mind-numbing activities (like building UIs), they had failed to build on the skills that would have been useful for the higher-up-the-value-chain job I was recruiting for (finally that team went to IITs and got a bunch of campus hires. They gave up on lateral hiring altogether). End of Digression 2.

Those two digressions weren’t particularly meaningless. I guess you know where this post is headed now. So, the thing with a job is that along with the short-term benefits it provides, it should also help you build on those skills that you think you can monetize later on in life. Every job (most jobs, really) teach you something. There is constant learning everywhere. But what matters is if the learning that the job offers is aligned with the kind of learning that you think you are geared for, which you think you can monetize at a later point of time in life.

I still claim that I work for money, but just that I take a longer-term view of it. And I strive to learn those things on a job which I think will be helpful for me in terms of monetization at a later point of time in my life.

 

Bilateral Crib Arrangements and Correlation

People say that cribbing is in general good for health, and I heartily agree. I love to crib. Occasionally I bore the hell out of my listener with my cribbing. And I’m sure the readers of this blog have also been on the receiving end of this on more than one occasion. There have been occasions when I’ve been specifically asked not to crib, and others when people have tried to subtly indicate to me that they are not comfortable with my cribbing.

In order to prevent the latter problem (of boring someone with my cribs and them not being able to directly tell me to shut up), over the last few years, I’ve entered into several informal “Bilateral crib arrangements”. Ok – I’ve never used that term before – in fact, I invented that term only some two or three days back. But that doesn’t take anything away from the nature of the arrangements.

So a bilateral crib arrangement is an informal arrangement you get into where you agree to listen to someone’s cribs and lend a friendly shoulder wiht the implicit agreement that they return the favour. The terms of the arrangement are never really described in that many words but that is essentially what it is. It usually has a component where one party says “ok let’s change the subject now” or something to that effect, and the counterparty replies “no no it’s ok you can crib on”.

Occasionally I’ve also gotten into one-way arrangements – where I either only put or receive cribs, but dont’ do the opposite action. Basically this happens when one of the two parties is more comfortable with the ohter than the opposite relationship, or if one of the parties alreeady has enough crib-receivers and doesn’t need one more, but is happy to receive cribs. Though some of them have lasted, occasionally I’ve felt uncomfortable in those – assymetric relationships create mental obligations.

So coming to bilateral crib arrangements – the biggest threat to these arrangements that I’ve observed is what I call as correlation. For a bilateral crib arrangement to work effectively, it is useful if one party is in the position to receive cribs while the other wants to crib. The situation when both don’t need to crib is also good. The problem occurs if both parties want to crib and want to crib to each other.

I’ve been through this several times and it hasn’t really been pleasant. On a number of occasions, I’ve had to back down and somehow bring my cribs under control while lending a friendly shoulder to my crib-partner. On others, I’ve visibly noticed crib-partners putting up with my cribs just so as to not create conflict. Such situations are suboptimal for both parties involved, and need to be avoided.

In this regard, it is important to choose a crib partner whose correlation with you is low. That way, the chances that both of you will want to crib at the same time to each other is low, and the awkward situation of competitive cribbing or backing out can be avoided. I don’t really know how you can choose people with low correlation with you, but I supopse you’ll have to take a few data points and extrapolate. Also avoid people whose correlation with you is obviously high – such as collagues.

Another effective tool in cribpartner management is to be diversified. You need not have several bilateral crib arrangements, but with a judicious combination of unidirectional and bidirectional crib arrangements, keeping in mind various time zones, you can ensure that there is a receiver to listen to you whenever you want to crib.