Pharmaceutical products are put through a rigorous process of scientific and clinical evaluation before they are introduced into the market. These studies seek to establish that the product in question is both effective and safe enough for human use. Because preventive vaccines, unlike drugs, are typically devised for use in otherwise healthy people, regulators typically require that there be few if any side effects associated with their use.

Like any pharmaceutical product, a candidate vaccine begins its journey to the market in the laboratory, where it must be shown in animal studies to be nontoxic and, at a minimum, to provoke a vigorous immune response against a pathogen of interest. If it meets those criteria, it is then evaluated for its safety and ability to prevent the disease it targets in clinical trials that involve human volunteers.

These are generally conducted in three sequential phases. Data collected from such trials are submitted to regulatory agencies for review. If the data pass muster, regulators approve the vaccine. The entire process is about as time consuming as it is indispensible—it typically takes a decade or more just to move a vaccine through all three phases of clinical development. IAVI and its partners subscribe to the highest scientific and ethical standards for conducting trials of AIDS vaccines, keeping at all times a keen eye on the wellbeing of trial volunteers. Our adherence to those standards is monitored by multiple agencies and independent auditing bodies in a variety of countries.