The International AIDS Vaccine Initiative (IAVI) will fund testing of a new kind of preventive vaccine, which has been developed at the Institute for Human Virology (IHV), started in 1996 by Robert Gallo, M.D., at the University of Maryland. IAVI funds promising AIDS vaccines under intellectual-property agreements which will help make successful ones available at affordable prices to developing countries.

The new vaccine will be taken orally, and could possibly cost less than $1 per dose to produce.

Several aspects of this technology are particularly important:

1. There are many advantages to vaccines which work by delivering DNA which instructs cells to produce the specific proteins against which immunity is needed. But ordinarily DNA could not be taken orally because it would not reach the places it needs to go. The new technology uses a salmonella bacterium which has been genetically modified so that it does not cause disease -- and also genetically modified so that it includes selected parts of HIV.

   The salmonella bacterium "knows its way around the gut," and delivers the selected DNA directly to dendritic cells in the intestinal mucosa, which may be particularly effective for providing "mucosal immunity" to prevent HIV infection. This is important for blocking sexual transmission of the virus.

2. This bacterium has plenty of room to carry added DNA, allowing great flexibility for modifications. If the first vaccine does not work, different versions can easily be made by trying other parts of the virus. And this vaccine can be customized for the different viral strains which cause epidemics in different parts of the world.

3. The six standard children's vaccines cost less than $1 to produce (for all six), but $15 or more per person to deliver in developing countries, because of the need for sterile injection, specially trained health workers, etc. An oral medication should be much less expensive to deliver.

   This vaccine is well along in its development, but clinical trials are still more than a year away. The first trials will take place in Baltimore and in Uganda, where the Ministry of Health is an active participant in this program. One trial will compare this vaccine head to head against an injected formulation which uses the same active ingredients but a very different delivery system -- a vaccine also being funded by IAVI.

"The driving force for this decade-long effort [to create the new vaccine] has been the development of a simple delivery system for an HIV vaccine that can be administered without needles and that can be afforded by developing nations. Salmonella-DNA has these attributes built in from the start. We are extremely excited now to be able to evaluate this strategy in human volunteers," said Dr. George Lewis, Director of the IHV Division of Vaccine Research.

For more information on the Institute of Human Virology, see http://www.ihv.org; for information on IAVI, see http://www.iavi.org.

ISSN # 1052-4207

Copyright 2000 by John S. James. Permission granted for noncommercial reproduction, provided that our address and phone number are included if more than short quotations are used.

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