I HOPE YOUR CHILDREN CATCH A VIRUS

Not any disease, rather a specific one, and for a good cause.


The last memorable influenza pandemic was the "Spanish" flu of 1918-1919.

- It killed ~3% (some say 6%) of the 1.6 billion people who populated the planet at the time: somewhere between 50 and 100 million.

- People who died were mostly under 25, so a similar but less lethal virus that conferred cross-immunity must have done the round in 1893.

- Mortality was 10-20% of people who, looking at the symptoms, seemed to be infected.

If this happened again today, with 6.5 billion people around, 195 to 325 billion people would die.



For that level of damage, three conditions are required:

1- The virus must be highly infective.

2- The population must not have immunity.

3- The disease must damage a vital organ, or impede its function, but not so suddenly that an affected person can't spread contagion widely.


In the case of the recent BIRD flu:

- Condition 1 was not met. Human-to-human transmission required a huge level of exposition to the virus, something like blowing noses in the same tissue, eating from the same spoon, or sleeping face-to-face. Most affected people had respiratory or food exposure to bird feces.

- Condition 2 was met: no immunity.

- Condition 3 was also met: the worst variants killed 70% of the few it did infect, despite their being hospitalized and carefully treated. In chickens (who were left untreated) mortality reached 95% (NINETY FIVE).


In the case of SWINE flu:

- Condition 1 was met: easy human to human transmission.

- Condition 2 was also met: relatively little immunity, especially among small children who were never exposed to a similar virus. More adults and older children were immune, so a similar virus must have spread just a few years back.

- Condition 3 was NOT met: the disease was even less deadly than the average influenza.


Both swine and bird flu viruses are mutations of viruses endemic in wild birds in Asia. Those viruses do little damage, like the common cold virus we always carry around with us: an annoyance that rarely turns really dangerous.

Howeever, such viruses will at some point mutate to combine all three conditions.  This will probably happen while the virus is hosted by humans or pigs.

It's not a matter of whether this will happen or not - it will.  It's just a matter of time. It may happen after our generation dies, or it may happen this year. Mysteries of disjointed stochastic events with low probability per unit of time.


Let us take a 15% mortality for infected people, compatible with the level observed in samples in 1918-1919.  Let us also take the death total to have been 70 million, compatible with demographic data.  These imply that number of infected people was 467 million, or 29% of the world population.

Now, let's make some optimistic assumptions for the 6.5 billions we are today: ann infection rate of 15% (half as much as in 1918),  and mortality of 10% (lowest in the 1918 range).  The result is 975 million infected and 97 million dead.

As an alternative, let's use the infection rate of 1918 estimated above (29%), and apply the mortality from the recent avian flu (70%):

1,319,500,000 dead, i.e. over 1.3 billion, i.e. over 20% of mankind.

In absolute terms, that is 13 times more than from the genocides and the infections brought to the New World from the old one, or from the Black Death in Europe in the 14th century. Closer to us, that is also 26 times more deaths than in World War II, including the Holocaust etc., or than killed by communism in China, and 57 times more than Stalin's victims.


Looking at the whole of human history, a 20% loss is not that terrible. Percent-wise,  the 30 Years' War in Germany, Black Death in Europe, and the Mongol invasions of China wiped out a far greater share of the local populations.  A loss in such a scale is nothing new, and there is no serious reason to believe it will never, ever happen again. And we know that humanity will survive.

On the other hand, the thought of a 20% population loss hitting your own  generation in a time span of a couple of years gives you pause.


I dearly hope I will catch the current strain. The risk of death from the current mild flu is low, but not zero.  There is also a possibility that the it might confer cross immunity to a deadlier strain. Obviously there is no guarantee that immunity will last decades - but it happened once already, which marks it as at least possible.

I am convinced that taking this risk, including a small risk of death, is better than not taking it.  I think this applies to children too. There are reports that some mothers in Britain looked back at 1918 and organized flu parties to get all their kids truly well smitten.

I hope all your kids get it.