Evidence and guidance on vaccine safety and effectiveness in subpopulations

This dissertation examines post-licensing vaccine safety and effectiveness against two major respiratory diseases in specific subpopulations, with emphasis on safety. First, inactivated influenza vaccination in pregnant women is reviewed, and a comparison is made of national influenza vaccine policies. Second, a systematic review is conducted and the pooled risk estimate calculated on the risk of disseminated disease from bacille Calmette-GuŽrin (BCG) vaccination in infants infected with human immunodeficiency virus (HIV). Potential impacts on immunisation programmes are considered for settings with different burdens of disease and levels of resources. Third, a review of the evidence-based management of BCG-related adverse events is performed, towards developing useful guidelines for healthcare providers. There may be little pre-licensing data on a chemical drug or vaccineÕs profile in subpopulations, although certain groups may be more vulnerable to the disease. As described, post-licensing studies that evaluate subpopulations provide vital information because these groups are often excluded in clinical trials as well as neglected in drug development. The immunological mechanisms of vaccine safety and effectiveness play a key underlying role in the differential risk of adverse events from the natural disease or from the vaccination in certain subpopulations. Influenza and tuberculosis are respiratory infections having enormous global health impacts. Pregnant women and HIV-infected subpopulations are groups known to be vulnerable to certain infectious diseases. Continual, careful appraisal of the evidence for vaccine safety informs policy and upholds the public trust placed in immunisation programmes.