Thursday, August 30, 2018

Zero risk does not exist

No entry: radiation risk
We would like to live in a world where we run no risks, but that is impossible. Whenever we get into a car, cross the street, turn on the gas, or play sports, we run a risk. The most elementary acts of our life entail a risk: breathing polluted air; getting exposed to the natural radioactivity in buildings; passing under a roof just when a tile is falling down... We have always known that life is synonymous with danger, and we have adapted to that. In our time, however, it seems that the threshold of risk we are willing to tolerate has fallen down. In other words: we are now more cowardly.
The media are largely to blame. Trying to attract readers and increase their profits, they often encourage states of opinion close to panic. We can see it in the way many news are presented, especially those affecting health (mad cow syndrome, bird flu, SARS, type A influenza, whatever...); the viability of human life on Earth (global warming, collision with an asteroid); or the economy (times of crisis). Many of these threats are real, but they are systematically exaggerated.

Physalia physalis, Portuguese man o'war
The following headline was published in a major Spanish newspaper on April 30, 2009: Worse than the jellyfish: The Institute of Oceanography warns of the presence in the Mediterranean of the Portuguese man o’war, whose sting can be fatal. The text of the article clarifies: [A] researcher from the Institute of Oceanography explained that the sting can be fatal for people who have allergic responses. However, these are extreme cases. The headline, however, has already touched the sensationalist key. It is well known that the number of deaths caused by wasp and bee stings are more than those caused by all the other poisonous animals together, many more than those of jellyfish and Siphonophorae like the Portuguese man o’war. Imagine the following headline in a newspaper: Danger in the countryside. There are bees, whose sting can be fatal. Nobody would take it seriously, and panic would not be caused.
The trouble is that these states of opinion, close to panic, are often translated into irrational and wasteful actions by politicians. In a simulated study published in an impact journal, it was shown that, to stop an epidemic of hepatitis, it is enough to vaccinate 10% of the population in danger. Shortly after its publication, faced with a threat of hepatitis epidemics in Spain, the different regional governments were swept away by the domino effect and paid for the mass vaccination of all the affected population, thus spending ten times more than necessary.
In another recent simulated study, related to the epidemic of SARS that took place a few years ago in the Far East, four palliative measures were compared, and the conclusion was that the use of masks produces the minimum effect. Most effective was the rupture of the chain of contagion, by quarantining the sick and their families. Later, to fight the threat of a type A influenza pandemic, some governments ordered millions of masks, of doubtful usefulness, but of greater social acceptance than quarantine.
In 1995, the press published with large headlines the news that a scientific study had shown that the use of the contraceptive pill increases the risk of thromboembolism by 100%. As a result of the resulting panic, thousands of women stopped taking the pill. It is estimated that, only in Great Britain, there were about 10,000 more abortions. But looking at the original article one can see that the risk of thromboembolism in women who do not take the pill is 1 in 14,000. In women who take the pill, that risk rises to 2 in 14,000. True, a 100% increase, but was the panic justified?
Let us look at a few annual risks in Spain (figures from 2004 to 2008):

Risk of dying by electrocution at home
1 in 4,000,000
Risk of dying of influenza
1 in 75,000
Risk of dying of AIDS
1 in 40,000
Risk of dying by an accidental fall
1 in 30,000
Risk of dying in an automobile accident
1 in 16,000
Risk of being harmed by falling from bed
1 in 650
Risk of dying of cancer
1 in 433
Risk of dying of heart disease
1 in 365
Risk of dying next year by whatever cause (unborn excluded)
1 in 120
Risk of suffering a non-fatal accident at home
1 in 36
Pregnancies ending in abortion
1 in 6.4

The greatest current risk for the life of human beings in Spain is to be aborted during the embryonic and fetal phases. This enormous risk (over 15%) does not cause panic, for adults know they are not affected, and those affected cannot complain.

The same post in Spanish
Thematic Thread on Science in General: Previous Next
Manuel Alfonseca

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