email Dr Kerns
Or, more precisely, the question is: if the economic disincentives can be overcome, will it be possible to develop such a vaccine for the human immunodeficiency virus? The vaccine question needs to be phrased thus because economic disincentives may present serious obstacles to vaccine development.
4.1 Economic disincentives
Normal market forces are not favorable for enticing private pharmaceutical companies to commit themselves and their resources to the development of vaccines, and particularly not to the development of HIV vaccines. The expenses entailed by such research will be extremely high, the legal liabilities will be considerable, the probable financial return may be small, and the possibility of complete failure in the research is substantial.
4.1.1 Costs
Costs entailed by development
and eventual testing of candidate HIV vaccines will probably be
in the many hundreds of millions of dollars, and those dollars
would probably be invested with anticipation of no great probability
of success. Genentech Corporation in San Francisco, for example,
has invested $150 million in AIDS research and has not been able to bring a single product to market, according to G. Kirk Raab, Genentech's president and chief executive officer. Raab says that unless [we] come up with something that looks much more promising than rgp 120 [recombinant gp120 subunit vaccine], the company is not likely to continue to invest in AIDS vaccine research.
4.1.2 Legal liabilities
Furthermore, the legal liabilities
- that is, the potential for being sued by persons or groups who
feel they have been harmed by a vaccine - could be enormous, perhaps
also ranging up into the hundreds of millions of dollars. Historically,
these potential vaccine-associated liabilities have been enough
of a threat to discourage most pharmaceutical companies from making
serious investments in vaccine research. In the US, some congressionally
mandated measures have been developed to minimize these liabilities
in recent years, but HIV vaccine researchers still feel they need
to be fiscally cautious.
4.1.3 Financial
return
In addition, the possible
financial return on even a fairly successful vaccine is not expected
to be great, especially if the primary markets for the vaccines
would be in developing nations, where the setting of higher prices
for vaccines would probably be viewed as unnecessarily (and unethically)
exploitative.
In other words, the costs are expected to be high, the legal liabilities
are expected to be severe, and the financial returns are expected
to be modest. These are not the sort of market forces that would
normally induce a company to commit itself to investing in vaccine
research.
Supposing, however, that some solutions to these economic disincentives can be found (and I believe that economically creative solutions will eventually emerge), there is still serious question as to whether it will be possible to develop a successful HIV vaccine. For one thing, the scientific challenges are formidable.
4.2 Scientific
challenges
Whether it will be scientifically possible to develop a preventive
vaccine for HIV is, as yet, an unanswered question, but, since
a vaccine would be such a gargantuan boon for humanity, there
is a great deal of work being done around the world to develop
such a vaccine. In 1984, when the virus was first isolated and
the world was told - by Robert Gallo in the United States and
Luc Montagnier in Paris - that we had now discovered the infectious
agent that causes AIDS, public health officials and scientists
alike were confident that a vaccine could not be far away. On
Monday, April 23, 1984, the day that the discovery of "the
AIDS virus" was announced, US Health and Human Services Secretary
Margaret Heckler "took to the podium...to assert that a blood
test would be available in six months and a vaccine would be tested
in two years". Her optimism turned out to be a bit hasty.
In the intervening decade hopes for a vaccine have been raised
and then dashed several times, until some researchers have become
frankly skeptical that there will ever be a vaccine for this virus.
Dr William Haseltine, for example, Chief of the Division of Retrovirology
at the Dana-Farber Cancer Institute in Boston, is highly skeptical
about the hope for vaccine successes. Speaking at the 1993 annual
meeting of the American Association for the Advancement of Science,
he said, "Do you want to know my guess for the chance that
any of these vaccines that we're trying now will work? Zero."
He said, moreover, that much AIDS research is "a mistake
in the allocation of resources," because the chances of developing
an effective vaccine are so small.
This skepticism is, in many respects,
entirely warranted. In this chapter and the next three chapters
I will explain why this skepticism is warranted, and yet why vaccine
research will continue to be pursued in the hope that it may yield
some significant prevention for HIV infection. Drs José
Esparza, William Heyward, and Saladin Osmanov, Directors of the
effort for HIV vaccine development in the Global Programme on
AIDS (GPA) at WHO in Geneva, are certainly some of the most knowledgeable
specialists in the world in the area of HIV vaccine research.
The AIDS Vaccine Development Unit at WHO is presently spearheading
a major new initiative for HIV vaccine development, in collaboration
with the pharmaceutical industry. WHO wants to determine now,
or at least soon, whether a vaccine for HIV is indeed possible.
Drs Esparza, Heyward, and Osmanov are quite hopeful that an HIV
vaccine will eventually be developed, despite the skepticism of
some researchers.
The skepticism springs from an understanding of a) the nature
of the human immunodeficiency virus itself and b) the nature of
the way vaccines work. So we need to take a brief side trip to
elucidate one or two key characteristics of the virus, and to
review how the immune system works. (Readers who are fully familiar
with HIV and who are also familiar with the workings of the human
immune system, may choose to skip ahead to chapter 8, the discussion
of human trials.)