Tralfaz

Tag: risk

  • Innumeracy and the cult of anti-vax

    The last post was about an innate understanding of scale and scope, and how this lead to a general understanding of magnitudes.

    A real world example, and one that is top of the news lately is the whole “anti-vaccine” movement. This is the increasing tendency to choose to not vaccinate your children due to the faulty belief that vaccines are worse than the disease. Leaving that argument aside, lets apply this “scale” thing to the antivaccine argument:

    Measles, a once common childhood disease, has several bad results, with the death rate being on the order of 3 per 1,000 infections. (I will admit that I am horrified by how high this is.) That means that if 1000 children contract the measles virus, 3 will die. Let that sink in. That is a 0.3% fatality rate. Seems pretty low, until …

    The MMR (Measles, Mumps, and Rubella) vaccine has pretty much eradicated the disease. In 2000 there were virtually no cases reported in the USA.

    Of course, the vaccine is not risk free. The major risk is an allergic reaction to an ingredient, usually the albumin (protein from the white of an egg), causing an anaphylactic reaction. This is somewhat on the order of less than one event per million doses. That is almost three orders of magnitude lower than the risk of death. (1/1000 the risk). And guess what, when you get a vaccine, the healthcare provider has an epi pen ready for the vanishingly rare anaphylaxis, so even if you do have such a reaction, you will get immediate treatment for it. There is also a more common reaction, of a fever, a rash, and other symptoms, all of which are far less risky than the disease. None of these are considered life threatening.

    So, the risk of a vaccine adverse reaction is 1/1000th the risk of DYING from the disease itself.

    The truly horrifying statistic is the rate of death in immunocompromised victims of measles. That mortality rate is a staggering 30%. That means that if your child is immunocompromised, and contracts the disease, they have a nearly 1 in 3 chance of dying.

    Summary

    The general population is poorly prepared to weigh risks, and scale. Clearly, the benefits of vaccinating your children vastly outweighs the risks with vaccination, but the specious arguments bantered about highlight how little
    the general populace understands the scope and scale of the risks.

  • My, how risk averse we have become

    On my bike ride today, I was pondering the changes that have happened over the last 20 something years. When I first got seriously into cycling in my mid 20’s, I thought nothing about climbing on, and doing 30, 40 or even 50 mile loops, barely taking a couple of bottles of water with me. Living in the south SF Bay Area, there were abundant great roads (and trails) to explore and enjoy. And enjoy them I did. One day, I rode over highway 9, through Davenport, out to the coast, up highway 1, and back through Bonny Doon to the bay area again. Probably 65 miles or so. Never thought twice about it.

    To be fair, I had some mishaps. One day, I had a major tire failure (sidewall blew out) at the top of Pierce road in Saratoga.  I had to hike about 6 miles back to civilization to make a phone call for a pick up. Or the time that I had a spill in Los Altos.  Ran straight into a block post. Bent my crank arm, and had to ride 12 miles home on a wobbling crank (that really messed up my ankle).

    Today, I think twice about going out, particularly when my wife isn’t around to rescue me. Granted, I am approaching 50, and have had some cardiac troubles, but the caution that I think about is really insane. I have my phone, I carry a first aid kit, I carry a lot more water (partly because I live in a desert and it is triple digits in heat), and I carry more emergency repair tools and parts than I ever did.

    Back in the late 1980’s, when I rode a heavy, low tech Specialized Allez, did all my own maintenance, I just rode. Suited up and away I went, 6 days a week (I worked the 1-9 shift, so I had ample time in the AM to ride). Now I do a lot more planning, I have my cell phone (which doubles as my heart rate monitor, and my exercise tracking), CO2 cartridges for fixing flats, and a fair assortment of tools to fix what ails me on the ride.

    Ah well, progress.