Thursday, December 9, 2010

Conventional vaccines: a remarkable history

The history of vaccines is often described as beginning in 1796, when Edward Jenner demonstrated that the technique of vaccinating people with the cowpox virus could provide protection against smallpox. 

Modern vaccine technology has subsequently protected many millions of people from the devastating effects of infectious diseases. A greater than 92% decline in cases and a 99% or greater decline in deaths due to diseases prevented by vaccines recommended before 1980 were shown for diphtheria, mumps, pertussis, and tetanus. Endemic transmission of poliovirus and measles and rubella viruses has been eliminated in the United States; smallpox has been eradicated worldwide.

The dramatic success of "conventional" vaccines has since inspired scientists to harness the body's immune system to tackle a host of other diseases with unmet needs, such as allergies, autoimmune diseases, cancer, and other infectious diseases. Unfortunately, the technological approach used to create the first vaccine successes does not lend itself to creating new immunotherapies against cancer, HIV, hepatitis C, and a legion of other deadly and disabling diseases.

Expanding immunotherapy boundaries

Significant scientific research investment has resulted in an array of new immunotherapy strategies. Some aim to down-regulate or better control an over-active immune system to tackle, for example, autoimmune diseases and allergies. Others are focused on up-regulating the immune system, as with conventional vaccines, to strengthen the immune response against cancers and infectious diseases.
Rather than using a killed or attenuated live version of a virus to induce a desired antibody response, as with conventional vaccines, new passive immunotherapies may directly introduce an agent such as a monoclonal antibody to conquer disease. New active immunotherapies such as DNA vaccines aim to stimulate not only a humoral (antibody) response, as do conventional vaccines and monoclonal antibodies, but also a cellular response, generating T-cells that can kill cancerous or infected cells. Inducing a T-cell response is considered a vital goal of immunotherapy research to achieve new vaccines capable of not only preventing but treating disease.
The growing knowledge and progressive clinical successes of newer immunotherapies (as indicated in the diagram below) are increasing scientists' conviction that harnessing the body's immune system against poorly treated diseases such as cancers and chronic infectious diseases is possible.

vaccine development firsts

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