Guidelines for conducting a Vaccine Trial

The guidelines to conduct the clinical trial on investigational vaccines are similar to those governing a drug trial. The phases of these trials differ from drug trials as given below:

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Phase I: The refers to the first introduction of a vaccine into a human population for determination of its safety and biological effects including immunogenicity. This phase includes study of dose and route of administration and should involve low risk subjects. For example, immunogenicity to hepatitis B vaccine should not be determined in high risk subjects.
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Phase II: This refers to the initial trials examining effectiveness (immunogenicity) in a limited number of volunteers. Vaccines can be prophylactic and therapeutic in nature. While prophylactic vaccines are given to normal subjects, therapeutic or curative vaccines may be given to patients suffering from particular disease.
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Phase III: This focuses on assessment of safety and effectiveness in the prevention of disease, involving controlled study on a larger number of volunteer (in thousands) in multicentres.

Some other points

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Some vaccines that contain active or live – attenuated micro organisms can possibly possess a small risk of producing that particular infection. The subject to be vaccinated should be informed of the same.
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The subjects in control groups or when subjected to ineffective vaccines run a risk of contracting the disease.
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The risks associated with vaccines produced by recombinant DNA techniques are not completely known. However, for all the recombinant vaccines/products the Guidelines issued by the Department of Biotechnology should be strictly followed.