HIV Vaccines - Accelerating the Development of Preventive HIV Vaccines for the World: Summary Report and Recommendations of an International Meeting

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* Safety: Safe in both the short and long term. Safety concerns include reversion to
infectious HIV, oncogenic potential, and immunosuppression in those vaccinated. The
vaccine should also be safe to deliver without prior screening for HIV infection (i.e., the
vaccine should not induce any adverse reactions when given to HIV positive individuals).
Although complete safety is the ideal, the risk to benefit ratio in populations at high risk of
infection may justify the use of a vaccine that has some risks or before every aspect of
safety has been exhaustively evaluated.
* Delivery: Provide long-lasting protection with a minimum number of doses (preferably
one), have a long shelf-life, be heat stable, and be simple to administer (preferably oral).
* Unambiquous marker for seroconversion: Provide health care professionals with a marker
which enables seroconversion due to vaccination and seroconversion due to infection to
be distinguished rapidly, easily, and inexpensively.
* Cost: The final price of the vaccine should be such that it will be affordable for wide-scale
distribution to all at risk of infection throughout the world.
2 Current efforts to develop HIV vaccines
2.1 Progress in HIV vaccine research
Since the discovery of the etiologic agent of AIDS there has been an unprecedented scientific
effort to understand its structure, function, pathogenic mechanisms, and routes of transmission.
More advances have been made over the last decade on this virus than on any other organism in
history, and new advances are being announced each week. The information from the ongoing
research efforts has provided the essential underpinning for efforts to develop preventive vaccines
and treatments for those infected. This worldwide effort has led to the design of a number of
different candidate vaccines which are currently being explored in the laboratory and in animal
models (see Table 1). These include:
* Peptides based on key portions of HIV structural proteins;
* Protein subunits based on HIV structural genes;
* Virus-like particles and other particles including pseudovirions;
* DNA that encodes one or more HIV proteins;
* Live recombinant viral and bacterial vectors that express one or more HIV proteins;
* Whole killed virus;
* ULive attenuated virus.
In addition, a number of new adjuvants and delivery methods are under evaluation.
A number of key scientific challenges, however, remain. These include:
* The nature of the immune response required to prevent HIV infection: Infection may occur
by both cell-associated and free-virus particles, and either through mucosal or systemic
routes of exposure. Whether specific mucosal immune responses will be required to
prevent infection and how best to stimulate them remains unknown.