There is only one thing that I know of for sure - we all die.
That may sound a bit more morbid than I am trying to be but it is a simple truth. We are born, we grow old, and eventually we pass on.
How long do we have on Earth? Who knows? Even the best actuarial tables and mathematical calculations get it wrong more often than they get it right. This is why life insurance is such a risky business at the level of an individual.
During the past 150 years, though, our life expectancy has changed. We are definitely living longer and healthier lives.
I should point out that life expectancy is a statistical measure of how long a person will live based upon expectations for a group of individuals. That is, if you have 10 people and five die at the age of five while the other five live to be 80, then the average life expectancy for the group is 42.5 years and yet no one actually only lived that long.
A better measure of the changes in our life expectancy might be "typical life span" or something like that. However, such measurements would be hard to define and calculate.
In any case, at the beginning of the 20th century, life expectancy at birth on a world-wide basis was 31 years of age. By 2010, that number had increased to 67.2 years. Yes, we have more people alive on this planet and they are living much longer. It is a large part of our population boom.
Why this has occurred is due to many factors, but public health measures are predominant in the list. Epidemiologists calculate that 85 per cent of the increase in our typical life span is a consequence of various public health measures.
Diseases such as diphtheria, measles, pneumonia, and influenza are not the deadly killers they were of old. Clean drinking water and proper sanitation has virtually wiped out cholera in the developed world. And childbirth is not usually a life threatening proposition due to sterilized equipment and medical professionals.
According to the Center for Disease Control in the United States, the number one public health measure in the 20th century was the introduction of immunization through vaccines. There is no doubt that vaccines save lives.
We often forget this in the developed world where most of deadly diseases have such a low incidence they have faded from our collective consciousness. It was not long ago, when I was a kid, that vaccines for the measles were not available and it was common for the disease to run rampant through a school. Now, measles are so rare in British Columbia that we can count individual cases.
We have effectively eradicated measles from our population although it still exists in other countries around the world. Vaccines have virtually eliminated many other diseases such as polio and diphtheria. Small pox is deemed to have been eradicated as a consequence of immunization programs.
A recent report in the journal Science goes one step further in analyzing vaccination against the measles. The measles virus acts as an immunosuppressant leaving people who have contracted the disease prone to other opportunistic infections. This is something that has been known for a number of years.
However, it has always been assumed the effect was short-lived lasting for only a few weeks at most. Using population-level data, the researchers were able to show that measles induced immunosuppression has a much more prolonged effect lasting from two to three years.
For a child, this serious harm to their immune system significantly increases the chance of infant or early childhood mortality. What is perhaps more telling is that the correlation between the measles and, say, pneumonia six months later has been missed.
In other words, measles itself might not kill a young child but it will allow other diseases to do so.
The introduction of mass vaccination against the measles has reduced childhood mortality rates by between 30 per cent and 50 per cent in resource-poor countries. In impoverished regions of the world, mortality rates have dropped by as much as 90 per cent after vaccination was introduced.
This effect is not simply a consequence of reduced deaths from measles itself. It has a fairly low fatality rate - somewhere around one in every 1,000 cases. But it is a consequence of not leaving children immune-compromised as a result of getting the disease.
The introduction 50 years ago of measles vaccines has resulted in striking reductions in childhood mortality and morbidity. Measles control has been one of the most important public health measures of the past 100 years and not just for controlling the disease itself. It has prevented millions of deaths from other opportunistic infections.
We are now living longer, healthier, and happier lives because of vaccines and other public health measures.
