Vaccines

According to the WHO and MeSH(Medical Subject Headings) scope note, vaccines are “Suspensions of killed or attenuated microorganisms (bacteria, viruses, fungi, protozoa, or rickettsiae), antigenic proteins derived from them, or synthetic constructs, administered for the prevention, amelioration, or treatment of infectious and other diseases.”

The earliest form of vaccination was variolation developed by the Chinese. Edward Jenner, the “inventor of vaccination” as he is called, was inoculated by variolation. He observed the relationship between the equine and bovine diseases grease and cow pox respectively. When a milkmaid told him that she could not catch small pox because she had had cow pox, he was intrigued. He tested out his theory on a young boy by infecting him with cowpox followed by small pox. As he predicted, the boy did not contract small pox.

Jenner's process came to be called "vaccination," after "vacca," the Latin word for cow, and the substance used to vaccinate was called a "vaccine." It is now used globally.

However, despite the worldwide immunization scheme, 20% infants around the world are still left un-immunized and are responsible for approximately two million deaths annually, especially in the remote and impoverished parts of the globe. This is obviously unacceptable; infected people may lower the herd immunity of the area they reside in and can cause rapid spread of the diseases. Un-immunization of so many has been attributed to the difficulties in production of vaccines, distribution and delivery.

DNA vaccines may be an alternative but they are expensive and don’t always have the desired immune response.

“Let thy food be thy medicine” said Hippocrates. Many scientists have tried to imbibe this sensible thought and have suggested genetically manipulated plants and plant viruses to produce vaccines against diseases such as diarrhoea, AIDS etc.
These vaccines are called edible vaccines and my subsequent blog entries will concentrate on this topic.

References:
a.http://www.accessexcellence.org/AE/AEC/CC/vaccines_how_why.php
b.Lal P, Ramachandran VG, Goyal R, Sharma R. Edible vaccines: Current status and future. Indian J Med Microbiol [serial online] 2007 [cited 2008 May 2];25:93-102.
Available from: http://www.ijmm.org/text.asp?2007/25/2/93/32713