Today, in 2016, researchers all over the world are searching for a vaccine for the latest virus to plague humanity...Zika. But disease causing viruses have existed for as long as humans have lived, and probably before that. A virus is an infectious agent that can only replicate itself within the living cells of another organism. It is too small to be seen, even with light microscopy, but at least 1000 years ago, Chinese scientists knew that something too small to be seen was causing infections and death.
There are at least 15 diseases for which vaccines are effective and recommended: Yellow fever, rabies, polio, tuberculosis, cholera, mumps, measles, diphtheria, and influenza, to name some of them.
Probably the most famous vaccination discovery was William Jenner's late 19th century discovery and development of a vaccine for small pox. Originally inoculation was used, but Jenner discovered a more effective method of immunization through the use of a vaccine. This vaccine was well known when Robert graduated from Queen's in 1908, as vaccination for small pox was compulsory in England from 1853 onward, and spread to other countries, thus eventually wiping out the scourge of small pox. It is estimated that before small pox vaccinations were instituted, this deadly virus killed 300 million people worldwide. Since the vaccine was developed from cowpox, perhaps the term "herd immunity" originated here? "Herd immunity" is very important as it means that when the vast majority of a population is immune, the virus cannot replicate itself and spread.
While there has been some controversy surrounding vaccines in recent years, people tend to forget what a difference vaccines have made to our lives. Small pox is gone, and how often do you now hear about typhoid fever in developed countries? The first vaccine for typhoid was developed in 1896, but many physicians recognized that a lessening of typhoid epidemics could also be achieved by insisting on a clean, uncontaminated water supply. Robert campaigned ceaslessly for this, but knew that the vaccine was also invaluable.
Diphtheria was another disease with which he had to deal. It is almost never heard of now that the vaccine exists. It was first developed in 1923, and gradually perfected.
In 1927, a vaccine for tuberculosis arrived on the scene. We don't think too much about TB these days, but it was very prevalent in the early part of the 20th century, so Robert and other physicians of the time were grateful for this vaccine. And, unlike small pox, TB has not been eradicated and could come back. Remember what a vaccine does is make your immune system strong enough to fight off specific viruses....and thus prevent them from replicating within your living cells and spreading to others who have not been immunized..
The power of the tiny virus is astonishing. Can you imagine yourself living in a world without vaccines to prevent and combat these killers?