Sunday, March 29, 2020

The Vampire Analogy

Let me tell you a story to illustrate some of the issues we are facing with the COVID-19 epidemic by analogy. Since most of us know more about vampires than about viruses, I'll use a vampire analogy.

In the story, the vampires have mutated from the original vampires: the sun does not bother them, so they can be out during the day. Anyone they bite also turns into a vampire, but just for a few weeks. Most people they bite simply turn back into regular people after 2 or 3 weeks, but a few of them die from vampire fever. Just like the original vampires, they are very hard to kill, and constantly want to feed. They are not afraid of crosses, but they hate the smell of garlic, and will not bite anyone who has just eaten garlic. But that's short-term protection that starts to fade after a few minutes, and is mostly gone after an hour. You can refresh it by eating more garlic.

Our story starts in a mountain town called FirstTown in Transylvania a few hundred years back. A local doctor noticed that more people than usual got sick, and some of them died. On some of them, he noticed bite marks, so he tried to warn the town about a vampire problem. But nobody really believed him, except for some local trouble makers. Everyone went along with their life as if nothing was happening. Many more got bitten by vampires and, in turn, bit their family, neighbors, friends at work, and anyone else they could find. Some people got what looked like a cold after being bitten, and people started to wonder about the new cold. But most got over it quickly, and so it seemed to be no reason to be concerned. However, the number of vampires kept increasing, and some of the new vampires got very sick. When so many people got sick that the town ran out of rooms in the local hospital, the mayor could not ignore the problem anymore. He passed a curfew where everyone had to stay home. The local guard beat and jailed everyone who did not comply, so the streets were empty after a day. Anyone who was suspected to be a vampire was locked up into a room - sometimes with other suspects, sometime alone. To keep people from starving, the mayor send his guard out to distribute food. He clad the guards in knight's armor to protect them from vampires, and closed the city gates. A couple of months later, the town was free of vampires. But some vampires had escaped before the town gates were closed, and went to neighboring towns.

The next town over, SecondTown, remembered similar vampire problems from the past. As soon as they heard about the problems in the FirstTown, they inspected every single person who wanted to enter through the city gates, and told the local doctors to watch out for any signs of vampires. Despite the controls, some vampires slipped through the gates undetected. But the doctor warned the mayor about anyone who showed the slightest signs of vampirism, and the mayor locked them up for a few weeks, just to be safe. He also warned the people living in SecondTown to not go out unless absolutely necessary, and closed the schools and some of the stores. Anyone who needed to go out to get food or visit a doctor had to eat a clove of garlic every 10 minutes to protect them from any vampires who went undetected. To make sure that there was enough garlic for everyone, the mayor told the farmers in his town to convert any corn fields to garlic fields. Fortunately, many of the farmers had done this already after the last vampire problem. Some people started to buy up garlic in large amounts, intending to sell it at a big profit to those in need, but he mayor issued new laws that had severe fines for profiteers. After the first profiteer was beheaded, and his head hung out on the market place with a big sign under it explaining his sins, the profiteering stopped.
But the mayor wanted to make sure that everyone who needed to go out would be able to get garlic, so he rationed it, and told merchants to closely track who had bought garlic, lest someone would show up at the store many times a day.
Thanks to the strict measures implemented by the mayor, and followed by almost everyone, SecondTown saw very few vampires. Every now and then, a starving vampire from FirstTown would crawl over the city walls at night undetected, but they rarely found anyone to feed on who was not reeking of garlic, so most of them just converted back after a while. Sometimes, residents of SecondTown would return home after a trip to FirstTown, but they would all be locked up for weeks until it was clear that they were not vampires, or they had reverted back into normal people.

Across the sea from SecondTown lay any another town, ThirdTown. Some people in ThirdTown had heard about the vampire problems in FirstTown, but nobody worried - everyone knew that vampires do not cross the sea! But when the first vampires were seen in ThirdTown, they remembered stories told by some crazy bard about vampires traveling in coffins. Quickly, they closed to city gates, but it was too late - some vampires had slipped in undetected, and started feeding and making new vampires quickly. The town tried to track track everyone who had been in touch with a known vampire, and put them under house arrest, but there were too many vampires that nobody knew about. Soon, the first deaths from vampire fever were reported. The mayor made a big speech on the market place, telling everyone to stay home if possible, so they would not get bitten. But many did not believe him, or thought that it was not that bad, and just ignored him. So the vampires happily kept feeding and multiplying.
As the number of vampires in ThirdTown grew, the mayor realized he needed more drastic measures to prevent the death of many people. He thought about telling everyone to eat garlic, but most garlic had been imported from FirstTown and SecondTown, and these towns kept the garlic for their own use. After talking to the farmers and realizing that there would barely be enough garlic to keep the doctors safe, the mayor told his people that regular people should not eat or buy garlic. To make the argument more convincing, he let others tell stories that garlic did not really work against vampires.
As the number of vampires in the town kept going up, the mayor kept telling people louder and louder that they should stay home; when they did not listen, he told the guard to issue fines for anyone on the street without a good excuse. What else could he do, without enough garlic and too many vampires for his guard to trace?
Eventually, the number of vampires seen in ThirdTown started to go down. New vampires still were seen, but their number did not change much, and many previous vampires were converting back to non-vampires. But the toll in ThirdTown was still tragic - many had died from vampire fever.

Across another sea lay a big city, ForceCity, also known as FC. When the first vampire was seen several weeks after the first reports in FirstTown, the FC mayor closed all ports foreigners, and then considered the city as being safe from vampires. But some vampires had slipped in already, and started biting and multiplying quickly. The FC mayor tried his best to ignore the problem, since most people were just fine a few weeks after being bitten, and all those people staying in their homes were really bad for business. When numbers kept rising, the mayor held a speech, asking people to stay home so they would not get bitten. Some people ignored him, but many tried to follow his advice. But of course, everyone had to go shopping every now and then, not realizing that vampires loved hanging around supermarkets to find new victims. Those lucky enough to keep their jobs kept going to work; that included those already converted to vampires, who found the work places a rather convenient place to feed. Vampire counters soon found that the number of vampires in FC was higher than in any other town in the world, and growing more quickly than in most other cities and towns. Numbers in ForceCity keep going up...
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I am telling this story as a vampire story because viruses are such teeny little things that we can't see, and barely understand. Thanks to Bram Stoker, countless other authors, and TV, though, we all have a good idea what vampires are like. I had to modify them a bit, mostly by making vampirism temporary and by eliminating their sensitivity to sunlight, but otherwise, they have quite a few things in common with viruses - especially the tendency to exponentially multiply if left unchecked.

The towns should be easy to identify: FirstTown in the story is obviously China; SecondTown is Taiwan, but Singapore, Macau, South Korea, and Japan are similar; ThirdTown are many countries in Europe and other parts of the world; and USA = FC.

For the vampire- and virus-fighting measures, some are easier to understand than others. Staying at home works for both: neither vampires nor viruses can enter a house uninvited. Sending the city guard out to find and lock up vampires is the same as "test, track, quarantine", which is one important component in the measures in Taiwan and other asian countries that have contained the virus; but it is only possible when the number of infections is small.

The garlic eating is a rather important analogy, as is my modification that it works only a short time. The equivalent to garlic eating is widespread use of face masks by the population combined with widespread availability of public disinfection stations. Masks reduce the spread of infection by containing droplets - here's an image if you need one:
Those droplet contain a lot of virus, waiting for anyone to infect. Most of them quickly fall and settle on surfaces, waiting to be touched. Once on your fingers, it is just a question of time until they get into your mouth, nose, or eyes, and infect you. Humans touch their faces about every 2-3 minutes, and that is a habit that is very hard to break. So that's where the "garlic works just a short time" comes from: washing hands and disinfecting only works until you touch a contaminated surface, or if you disinfect hands between getting virus on them and touching your face. Face masks can help to reduce "touch transmissions" because they cover mouth and nose; public disinfection stations help by reducing the time that virus is on your hands. Both measures are an important component of a successful containment strategy, especially in the long run where "stay at home" measures cannot be sustained.