Genetics study reveals how bacteria behind serious childhood diseases evolve to evade vaccines

Genetics has proven to scientists that vaccines used to combat childhood can fail eventually.  Bacteria can change disguises to avoid vaccines.  Pneumococcus causes life threatening diseases like pneumonia and meningitis.  Vaccines recognize these bacteria by the polysaccharides on the outside of the bacterial cell.  This vaccine has been used in the US since the year 2000 and has had remarkable effects.  When they introduced the vaccines in the UK, the results were not as successful.  Researchers observed that bacteria evaded the vaccine by coding a substance other than polysaccharides.  So the vaccine stopped recognizing the bacteria.  So as new vaccines are developed, scientists have to take into consideration that the genome of the bacteria can change so that the vaccine does not recognize it.  

http://insciences.org/article.php?article_id=10652#pics