The pandemic will not be over for a while yet

For the wine industry, the current pandemic has had serious financial consequences since February 2020; and these consequences are on-going even now, in December 2021. Well, the pandemic is not going to go away any time soon. So, as a biologist, I thought that I might try to clear up a whole series of issues that the general media seem to often get wrong. There is no further mention of wine in this post; but you will learn a lot, anyway.

Pandemics

A pandemic is an epidemic that affects whole continents. An epidemic, in turn, involves the wide spreading of some disease-causing pathogen (eg. virus, bacterium, fungus, apicomplexan). In each epidemic, the pathogen spreads easily among a large number of people (or other animals, and plants), causing them to develop a particular disease; and it may well cause a considerable number of deaths.

Medically, "situation normal" for diseases involves elderly people, because they can easily succumb to many diseases (ie. their personal immune system has become weakened). For example, every year, elderly people are encouraged to take a "flu shot" (a vaccine; see below) to help them cope with whatever the current widespread influenza virus happens to be. An epidemic (which is unusual, by comparison) therefore occurs when younger people are affected, as well as the elderly.

The current pandemic thus initially surprised the medical people (and the government authorities) when it started out principally affecting older people. Epidemics do not normally start like that, being common principally among older people. Sadly, a lot of old people died early on, before the authorities realized that this group needed special protection.

They are not the only risk group, however. Males are much more likely to get sick (and die) than are females, for example, along with people who have high blood pressure, or Type-II diabetes. Have a guess who is old and male, with family-inherited high blood pressure and Type-II diabetes? Sometimes, I think that it is not safe for me to leave the house!

SARS versus Covid

SARS-CoV-2 is a virus, a foreign piece of genome that can get inside living organisms (the hosts), and proliferate there. Covid-19 is a disease, which is the host body's reaction to that foreign genome. I would say that confounding these two things is the single most common mistake made by the media. They say that something, like a mouse or a hippo is, "infected with covid" when they mean "infected with SARS". If the infected mouse does not react to the virus, then it does not have Covid-19, even though it has (and can transmit) the virus. This confusion cannot help the general public to understand what is going on.

So, Covid is you, SARS is the virus — you get infected by the virus, and react by developing the disease. This distinction is vital to how we deal with the current pandemic (as discussed below). Some people react so well that they don't even notice that they are infected with the virus, while others get severe cold-like symptoms; and many react so badly that they die (officially, 5.3 million, so far, which is 20% of the number of officially reported infections).

Our immune system is our body's defense against foreign genomes (or other bodies). Our own body can heal a cut or scratch, but in addition the immune system deals with anything foreign that enters through the damaged area (that is what the pus is doing, for example). In particular, your immune system will usually remember how to deal with every pathogen that your body has ever encountered — every cold, every bout of flu, and every vaccination. Some immune systems do better than others, though, which is why we all differ in how we react to disease-causing organisms. Importantly, your immune system may not be able to deal with any of the pathogens that you have not yet encountered.

Viruses cannot live outside the host, which makes them different from all other pathogens. Bacteria have a cell wall, for example, and can maintain a separate existence. However, a virus is not a cell — that is why we often call them "particles", not cells. They do not last all that long in the open air.

This means that a virus needs to get from one person to another pretty quickly. The easier they can do this, the more contagious they can be. Moreover, killing the host is a pretty bad move, because the virus dies along with the host. That is, the virus needs to keep the host alive, so that the host can continue to spread the virus particles to new hosts.

In this sense, an infected person who is not sick is the worst possible scenario for us, but the best one for the virus. During the course of an epidemic, new virus genomes continually appear, due to genetic mutations (viruses mutate easily) — in the current case, these variants have been called Delta and Omicron, and so on. Through time, these new variants are usually much more contagious than their predecessors (they spread more easily), but they are less likely to be deadly. So far, this looks to be true of the new Omicron variant: it is highly contagious but seems to cause milder symptoms — this is exactly what we would expect, based on previous pandemics.

As another example, the immediate predecessor to SARS-CoV-2 was called MERS. It was far more deadly than its own predecessor, called SARS. As a result, MERS did not spread beyond the Middle East, where it arose — it killed people before they could spread the virus particles. It thus did not cause a pandemic, and was thereby safe for the rest of us. SARS-CoV-2 is another matter entirely, compared to both SARS and MERS. Without action from us, the only way this pandemic is likely to end is to wait (who knows how long) for a variant to become predominant that does not kill at all.

Incidentally, the coronaviruses, as a group, are so problematic because they normally do not kill humans. Indeed, they are one of the causes of the common cold — about 15% of all colds are caused by coronaviruses, and so most us have been infected by one at some time or another. Colds are so common because the virus particles spread easily, but do not kill their host — the host just soldiers on, spreading the particles to new hosts. So, in one sense, SARS-CoV-2 is simply a mutant cold virus that can kill. (Note: there is no known cure for a cold — we solely treat the symptoms.)

Vaccines

Since your immune system may not be able to deal with any of the pathogens that you have not yet encountered, we usually need to do something about any new epidemic. That is where vaccination comes in — we give your body some sort of (safe) experience of the new pathogen, so that your own immune system can work out what to do about it. This vaccine* will protect you when the real thing turns up.

Think of it like a seat-belt in a car. The seat-belt does not prevent you from having an accident, but it can help tremendously with your reaction to the accident. Indeed, the seat-belt can keep you alive; and all cars are now fitted with them, by law.

Well, a vaccine is a seat-belt, nothing more. It cannot stop you from catching a virus, but it can help enormously with your reaction to the virus infection, preventing development of the disease. So, yes, it is perfectly normal for vaccinated people to get infected, although we would prefer that this does not happen. However, the vaccine should stop people from dying in response to that infection.

So, when driving a car, you still have to drive safely, even though you are wearing a seat-belt. Similarly, you still have to keep away from infected people (ie. socially distance), even though you are vaccinated. This virus is spread by aerosols, which are the finest suspensions in the air — distance is your best way not to breathe in infected air from another person. Remember, though, just like a seat-belt, a vaccine cannot guarantee to save you, although it will greatly improve your chances.

So, can you all now see why we are still having global problems? People are sick and tired of the whole affair, and want it to be over. So, they get vaccinated, and immediately try to return to a "normal" life. That is like buckling up a seat-belt and then driving without regard for the road rules. The best approach is to drive safely, even if you have filled your car with safety devices.

This is why the pandemic is not going away any time soon. You are still being subjected to infected people in your vicinity, even when you are vaccinated. The vaccine will help with your immune reaction, but not with your original action in contacting the infected person in the first place. While-ever there are infected, or potentially infectious, people on this planet, the pandemic cannot become history.

Protection thus ultimately comes from group behavior, not from the behavior of individuals — we all need to be uninfected, not just some of us (medically, this is called "herd immunity"). Your biggest danger is not the virus itself, but the people who refuse to protect themselves from it, and can thus infect you, whether they intend to or not — the virus cannot harm you if there is no-one to give it to you.

In the meantime, my wife and I still behave like we are elderly people in a pandemic that can kill us, even though we are both fully vaccinated. We still keep as far from other people as we reasonably can — for example, we visit the supermarket when it is not busy, and we prefer to attend outdoor events (like Christmas markets, at the moment).

The worst pandemic in history

Many people consider the Black Death to have been pretty bad, because a larger percentage of the known world population died, compared to any other pandemic. This was a plague epidemic, which is caused by a particular bacterium (not a virus). There have been plenty of plague epidemics in history. Indeed, the Bible is full of them — many of the catastrophes attributed to God's displeasure are now recognizable as having been plague epidemics.

However, the pandemic that killed the largest number of people occurred only a century ago, not a millennium. This was another viral epidemic, caused by an influenza virus. These are pretty common, too, often under the name "swine flu" or "bird flu". They have these names because we often share so-called H1N1 influenza viruses with pigs and birds (apparently we have a lot of physiological similarity to them!). The most recent such pandemics were in 2009, and before that in 1977. (Aside: One reason that we have dogs and cats as domestic animals is because we don't share pathogens with them — you certainly won't catch Covid-19 from them, or give it to them.)

So, one common scenario is that migrating birds spread the influenza viruses to where there are pig farms. The viruses infect the pigs; and new viral genetic variants then arise in those pigs. These new variants then get into the farmers, and they spread from there to the rest of us. The problem is that even if the new viruses do not kill the pigs, these new variants can kill us.

So, where would we look for a lot of pig farms under a major bird migration route? If I was in the USA, I would look in Kansas. So, it is of no surprise that the so-called Spanish Flu of 1918 was first detected on Kansas pig farms. (The mis-naming apparently comes from official attempts at a cover-up, trying to maintain morale in Europe at the end of World War I — the Spanish were the main ones prepared to report the epidemic, and the label has stuck.)

In Kansas, the virus spread to the nearby troop encampments, where the men were to be sent to Europe. Well, the rest follows like night follows day. A set of trans-Atlantic troop ships is an ideal place to spread a flu virus. When the infected troops turned up in Europe, what did they find? A set of field hospitals with half-dead soldiers, which is another ideal location for spread; along with a set of towns bombed to pieces, so that the homeless people were all jammed into church halls, which is another ideal location. The official figures indicate that more people died in that pandemic than died in the actual War itself (both military and civilian combined).

So, thank your lucky stars that the current pandemic has been nothing like that one. We are all having a tough time, sure, but almost all of us will live through it, this time (and without the red crosses that marked the doors housing plague victims during the Black Death). So, buckle-up and drive safely — get vaccinated, so our societies can get to herd immunity sooner rather than later. You were vaccinated against all sorts of childhood diseases, and it did you a power of good (no more polio, tetanus, hepatitis, rubella, measles, whooping cough, mumps, diphtheria, chicken pox ...) .

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* Vaccination is one of the greatest contributions ever made to medicine, and it was made by uneducated women (anti-vaxxers take note). The "old wives tale" among cow maids (tending the cows on their summer pastures) was that they did not contract chicken pox because they got cow pox, instead. That is, catching the pox virus that we share with cows (which is not deadly) prevented them from getting ill from the pox virus that we share with chickens (which is deadly, and used to be one of the most common causes of child mortality). You can imagine how the (male, highly educated) medical people responded to this claim. Still, one of them finally decided to check it out; and (blow me down) the women were right. That is why we call it vaccination ("vacca" is the Latin word for "cow") — it's the cow treatment.