Subject: Unforeseen Obstacle Arises For AIDS-Vaccine Trials
Date: Published: 7/22/88 105 lines
Source:  WALL STREET JOURNAL. Copyright Dow Jones & Co. Inc. 

   Unforeseen Obstacle Arises
   For AIDS-Vaccine Trials
    ----  
   By Jerry E. Bishop
   Staff Reporter of The Wall Street Journal

   A formidable problem is emerging in the quest for an AIDS
vaccine:  Homosexual men are likely to be ruled out as
volunteers for testing the efficacy of such a vaccine when -- 
and if -- one can be developed.
   Among the various social groups most commonly afflicted by
AIDS, or acquired immune deficiency syndrome, homosexual men
have been the largest and most cooperative group for research
on the lethal disease.  And scientists have long assumed that
the 400 to 5,000 recruits needed for vaccine testing would be
homosexual men at high risk of infection by the virus.
   But in a newly published report, two federal scientists
note that "the incidence of infection in this population
(because of education efforts) has now decreased, which may
limit their capacity to be used in vaccine trials."  The
decline means that it would be difficult, if not impossible,
to know whether any encouraging test results were reflecting
the effectiveness of a vaccine or merely the continuing
change in life styles among a test population of homosexuals.
   The alternative, the report says, is that volunteers for
vaccine tests may have to be recruited from among drug
addicts and prostitutes -- groups that pose obvious
difficulties for a vaccine test.
   Whom to use for a vaccine-efficacy test is only one of a
host of problems facing the development of an AIDS vaccine,
according to Wayne C. Koff, chief of vaccine research and
development for the government's AIDS-research program, and
his boss, Daniel F. Hoth, director of the program.  In an
article published today in Science magazine, the two tick off
the multiple scientific obstacles facing just the laboratory
development of an AIDS vaccine.
   Moreover, they write, "even if an effective AIDS vaccine
were developed today and prepared for clinical testing,
several clinical research, social, legal and economic issues
could potentially impede the vaccine from being licensed,
marketed and distributed to the public."  Among these issues,
they point out, is the unknown liability of companies that
might produce the AIDS vaccine.
   Messrs. Koff and Hoth don't speculate on how long it might
be before an AIDS vaccine is generally available.  But their
report implies that, from the time one emerges from the lab,
it may be a decade or more before it could be marketed.
   One reason is that the incubation period for AIDS -- that
is, the time it takes the disease to appear in a person
infected with the virus -- runs two to five years.  A
vaccine's effectiveness might become apparent in as little as
three years if a large number of volunteers are vaccinated
and a high percentage of them are exposed to the virus.  If
relatively few volunteers are vaccinated and the exposure
rate is low, it might be five to eight years before it's
clear whether the vaccine works.
   The problem of human tests has always haunted AIDS
researchers, but it wasn't a primary concern because
scientists hadn't figured out how to make an AIDS vaccine.
Recently, however, preliminary safety tests involving healthy
humans have been started for at least two potential vaccines,
and the issue is gaining some immediacy.
   The first two phases of an AIDS-vaccine trial, which test
its safety and whether it spurs the body to produce
antibodies and other weapons against the virus, don't require
a long time or many volunteers.  But in the third and final
phase of the trial, researchers want to gauge the efficacy of
the vaccine.  They need large numbers of volunteers who are
free of the AIDS virus but in danger of contracting it.
   Ethical problems will complicate this third phase, the two
scientists say.  The more volunteers there are exposed to the
AIDS virus, the quicker researchers will learn whether the
vaccine works.  But, the report notes, "researchers carrying
out the trial have an ethical obligation to inform, educate
and counsel the volunteer against high-risk behavior" that
might expose him to the AIDS virus.
   Having to turn to such groups as drug addicts and
prostitutes for volunteers -- assuming enough could be
recruited -- could complicate vaccine trials even further.  It
will be necessary for researchers to keep track of volunteers
for as long as five years and to know their drug and sexual
practices during this time.  This may be extremely difficult,
considering that the volunteers are engaged in illegal
activities.
   "Partners and spouses of (AIDS-infected) hemophiliacs are
at high risk of acquiring infection and would be expected to
be highly motivated as vaccine volunteers, but the limited
numbers of these persons diminish the prospect of evaluating
vaccines in this population," the report adds.
   Testing an AIDS vaccine overseas -- particularly in
Africa, which has a significant AIDS problem -- is a
possibility, the report notes.  But in addition to the
socio-political problems this would pose, there is a
scientific one.  A second AIDS virus now circulating there
would necessitate a more complex vaccine.

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