11.   Francis said one deterrent to getting more volunteers has been a fear that the experimental vaccine may actually infect volunteers with HIV.

12.   His search quickly turned up an experimental vaccine program at the Memorial Sloan-Kettering Cancer Center in New York, and he told Ms. Reinsch about it.

13.   Ho said he was deeply concerned how the editorial would affect the future of studies to evaluate experimental AIDS vaccines in developing countries.

14.   If the experimental vaccine was contaminated, nothing could have been done about it because tests for the ancestor virus did not exist then.

15.   In addition to recommending the experimental vaccine, which Argerich is taking, Morton explained that she would have to undergo surgery to remove cancerous tissue from her lungs.

16.   In the work with experimental AIDS vaccines, some temporarily forge ahead, only to be nudged out later by others.

17.   Last week, he became the first local person to participate in testing of an experimental AIDS vaccine.

18.   Lederle Laboratories and North American Vaccine Inc. also developed versions of the experimental vaccine.

19.   Letvin was quick to point out the many unknowns surrounding the experimental vaccine.

20.   More than a dozen experimental AIDS vaccines have been tested in a small number of people in this country.