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The Science of Superspreading

Bottom line: in order to stop (or realistically, suppress) the COVID-19 pandemic, we need to deal with hot spots of transmission a.k.a superspreading.

These days it seems like everyone and their pet wombat has become a COVID-19 expert overnight. I’m including myself in this category of ‘experts’, because in reality, I’m not an epidemiologist or infectious diseases physician. That’s why I’ve largely refrained from writing about COVID-19, apart from sharing important information every now and then such as this article entitled Should I Wear A Mask In Public All The Time? (published in early April this year).

However, that doesn’t mean we shouldn’t continue to learn about the disease. I strongly believe in educating the public, so that we can make informed decisions about what to do as a society trying to weather a pandemic.

This week, I strongly suggest that you spend a few minutes reading this article on ‘The Science of Superspreading‘. Despite the scary-sounding title, it’s actually really easy to read, and comes with some excellent illustrations in case you’re one of those people who feel faint when confronted with a wall of text.

As shown above, the key takeaway point is that:

Most people don’t infect anyone else. A small percentage of people cause most of the transmission.

For the general public, I think the above point is the most important thing to understand right now. But if you’re a card-carrying member of the Nerd Alert Society, then you might want to start reading about k.

Oh man, we’ve just spent ages trying to understand r, and now you want us to learn a totally different letter of the alphabet?

Err, yeah!

So if R0 (R nought) is the number of people, on average, infected by a single infected person, then k is the measure of dispersion for the disease. It’s a way of asking: does the virus spread in a steady manner or in big bursts? Here’s a really good article by Zeynep Tufekci on how ‘This Overlooked Variable Is the Key to the Pandemic‘.

So what?

If you accept that superspreading is an important feature in COVID-19, then it becomes obvious that we should promote measures that prevent superspreading. This is the rationale for avoiding the three Cs:

  • Crowds
  • Close contacts
  • Closed spaces with poor ventilation

The article also mentions backward contact tracing, but I think that’s more relevant for the authorities. So yeah, that wraps up our lesson for this week. Remember kids, ‘knowing is half the battle’!

Meanwhile…

As I’m writing this, Oxford has just entered Tier 2 of COVID-19 restrictions in the UK. This is probably the least surprising bit of news this week for me, considering the rapid rise in the number of infections here.

I’m not knowledgeable enough to come up with a fool-proof solution for the pandemic, so I don’t envy the authorities who actually have to deal with it. Increasingly though, I see people protesting against the myriad of restrictions imposed on the community. Here’s a picture I took on the 9th of October in the city centre:

COVID-19 protest

Instinctively, I feel like this is not the best response to our current situation (to say the least). But on the other hand, I fully recognise how lucky I am not to have to worry too much about work, health, finances etc. As more and more restrictions come into place, I can’t help but wonder how people will cope psychologically.

So if you’re reading this, I’d like to encourage you to reach out to your loved ones, check on them, make sure they are OK even if you can’t physically be with them. It may not seem like much, but to some people, it may mean the world to them.

Stay safe…

Update:

Thank you Dr Ahmad Munawwar Helmi (over on Facebook) who pointed out this article written by father and daughter team, Dato’ Dr Musa Mohd Nordin and Dr Husna Musa, on the need to think beyond R0 and movement control orders.

By Imran Idris

I am a husband, father, son, neurologist, neuroscientist-in-training, Tolkien-fan, and owner of two toy wombats named Mulder and Scully.