BCG vaccine for tuberculosis
- By:groshan fabiola
As any other health problems tuberculosis needs to be treated. While treating is not as easy at it seams, specialists tried to develop a vaccine to prevent it. Nowadays we know a vaccine for tuberculosis that is called BCG or Bacille Calmette Guerin. This vaccine was first used in 1921 and it is the only vaccine available in our days for protection against tuberculosis. Some categories of people, such as children are more protected than others after taking this vaccine.
The development of the vaccine took place in the beginning of the last century when Calmette and Gurein, two scientists from the Institute Pasteur isolated a live attenuated strain of Mycobacterium bovis. This strain was subcultured every three weeks for many years. After about thirteen years it was proved that the strain was less virulent for animals such as cows or guinea pigs. During all those years of research some genetic changes occurred to the original strain o Mycobacterium bovis. Those altered organisms were called BCG.
Nowadays there are several strains of BCG. As a vaccine against tuberculosis, BCG was first used n 1921. The cultures of BCG were distributed later to several laboratories all over the world where the vaccine strain called BCG continued to be cultured. After a while it was proved that the strain spread all around the globe had no longer identical genetic properties. Even the original strain maintained in Paris continued his change. To limit these changes the organism is maintained in several laboratories using a seed lot production technique to limit the genetic variations using freeze-dried cells so that each batch starts with the same cells.
Since the day of its first usage more than 1 billion people used this vaccine. It is known that for the first time this vaccine was given to children, after extensive tests in animals.
Until now, no problems seemed to occur after the usage of this vaccine, but the specialists believe that persons who are immune compromised might be at risk for developing serious infections caused by the BCG itself.
A tragic accident took lace in Lubeck where more than 25 % of the children that received this vaccine developed tuberculosis. Later it was proved that this was an accident and the cause of the created situation was a batch contaminated with a virulent strain of M. tuberculosis.
The BCG vaccines that are in use at this moment are produced in different areas throughout the world and it is known that they are not identical.About the author:
So, if you want to find more about tuberculosis treatments or even about mycobacterium tuberculosis please click this link http://www.tuberculosis-center.com