Alleviation of pain associated with immunization injections.

Typically any new vaccine (or for that matter any new drug) has to undergo phase 1 (early safety and dosing study), phase 2 (safety, dosing and immunogenicity study) and phase 3 (field efficacy and further safety study) trials before being licensed(2). In case one brand of the concerned vaccine with satisfactory efficacy data is already licensed, and serological correlates of protection for the vaccine are clearly known, a new brand need not do efficacy trials and can be licensed provided it shows non-inferiority (not more than 10% lower than for the lower CI) in comparative immunogenicity trials. Such non-inferiority results will assume and extrapolate similar efficacy for the new brand as compared to the existing vaccine (what is called bridging studies)(3). The new brand has to show non-inferiority over the existing brand in seroconversion (not more than 10% lower for the lower confidence interval compared to the existing brand) and GMCs (not less than 0.5 times as compared to the existing brand).