Parameters potentially affecting interpretation of immunogenicity and efficacy data in vaccine trials: Are they adequately reported?

Objective: To describe and analyze the reporting of major factors interpretation of vaccination efficacy and immunogenicity trials in recently published studies. Data sources: Selected studies (n = 83) published during a two year period in five journals most likely to contain vaccine trials. Study selection: Studies designed as prospective efficacy or immunogenicity clinical trials in human subjects examining an experimental or existing vaccine. Data extraction: Primary factors (vaccine dose, number of doses, dosing interval, site of injection, vaccine route), as well as secondary factors (age, race, medical status, handling and manufacturing of the vaccines and concomitant drug use during vaccination). Results: Only 24% of those studies utilizing intramuscularly administered vaccines reported needle length, 59% described the anatomic injection site, and 10% described the injection technique used. Eighty percent reported the actual vaccine dose used and the number of doses administered. Seventy percent reported the interval between doses. Conclusion: A high proportion of recently published vaccine trials fail to report potentially important methodological details, which may hamper the interpretation of vaccine efficacy and immunogenicity trial results.