PAGE 8 T Q-Notes T September 20, 1997
JEFFREY GRANT KOENIG
ATTORNEY-AT-LAW
SUITE 760
THE ADDISON
831 E. MOREHEAD ST.
CHARLOTTE, NC 28202-2725
(704) 335-5471
reason for hope
The search for a
preventive vaccine
by The AIDS Writers Group
Special to Q-Notes
President Clinton promised to make the
development of a vaccine to prevent AIDS a
major commitment of the governments scien
tific institutions. While most activists were dis
appointed that the promise didn’t include ample
funding, the announcement does point out
some positive changes. The success of combi
nation therapies has meant that activists have
less fear that the successful development of a
vaccine to prevent AIDS would mean decreased
efforts in research aimed at treating and curing
HIV disease. In addition, the announcement
is a signal that many now believe that a preven
tive vaccine can be developed.
The idea behind vaccines
Vaccination is based upon an old observa
tion: some people who get better after being
struck with an illness don’t get it again. Vac
cines have a long history, going back thousands
of years to the Chinese who gave dried out
smallpox to uninfected people to lessen the
chances of getting the disease later. Modern vac
cines go back to Jenner and his introduction of
cowpox as a smallpox vaccine in 1798.
All of our immune systems have a built in
capacity to fight some germs (including a num
ber of viruses) and the diseases they cause. In
addition, the body’s immune system has the
ability to learn to recognize an unfamiliar germ
as an enemy. However, it takes time for the body
to learn to fight an illness it has never seen.
The time it takes to recognize a new illness and
learn how to fight it can be the crucial few days
or weeks that makes the diflFerence between a
disease easily defeated and one that causes seri
ous damage or even death. Teaching the body
to recognize a germ as an enemy is what a vac
cine does, so that when the body is exposed to
the real germ, it will recognize and destroy it.
In HIV, the virus makes tens of billions of
copies of itself in the first few days and weeks
after infection. Therefore, the virus ends up
infecting many parts of the body quickly. The
hope is that a vaccine would get the immune
system to attack so fast that the virus would
not have a chance to reproduce and spread, and
thereby HIV infection would be prevented.
Can a vaccine prevent AIDS?
Over the years, scientists have developed
vaccines to fight many illnesses. However, some
researchers believed that since the basis of a
vaccine is getting the immune system to fight
an invader, it might not be possible to develop
an effective vaccine because, unlike other vi
ruses, HIV attacks the immune system itself.
In addition, it is feared that because there are
so many varieties of HIV around the world,
and the virus is able to mutate so quickly, a
vaccine that recognized one strain of HIV might
not recognize another.
Others argue that a vaccine is very possible.
Among the reasons many believe this is so is
the possibility that some small number of
people are naturally immune to infection by
HIV. If researchers can find out how their
system’s successfully fought off the virus, it
might be possible to get other people’s immune
systems to do the same thing.
How a vaccine might work
For most diseases, the key to developing a
vaccine is to look at people who have acquired
a natural immunity to the disease or at people
who have recovered ftom the disease. Research
ers then look at the responses ofthose people’s
immune systems and attempt to find something
that will create that response in others. As our
knowledge of HIV disease increases, research
ers are gradually learning what types of immune
response won’t work and what types may work
to prevent HIV infection.
Creating a response is not difficult. After all,
the body responds to the virus. The difficulty
is creating the right response without infecting
people. The safest vaccine is usually the weak
est. For instance, one made up of small pieces
of HIV could involve almost no risk of infec
tion, but it might have the least chance of be
ing effective. Vaccines more likely to work in
volve giving people a weakened (scientists call
them “attenuated”) live virus. Some individu
als have somehow been infected with such a
weakened virus and they have remained healthy
for at least 12 years. Nevertheless, the safety of
such a live-attenuated vaccine is not so clear.
In some diseases, this kind of vaccine is used.
The oral polio vaccine is such a live-attenuated
vaccine, and about 8-10 people a year in the
United States get polio from the vaccine. It’s a
price society is willing to pay to avoid thou
sands of cases if the vaccine was not used. How
ever, until more is known about the safety of
such a live HIV vaccine, the decision to use it
will be difficult.
Over the past ten years, scientists have de
veloped a number of HIV vaccines and it ap
pears that many of them are safe. Some of them
have been shown to protect chimps and other
primates for at least one year. Unfortunately,
these vaccines have not been tested on enough
people to know if they work.
The time for trials
Clearly, more than in any other illness for
which a vaccine has been developed, getting an
AIDS vaccine will mean a lot of trial and error.
More time, more money and more experiments
with human candidates is the only way to de
termine if we are successful. The bad news is
the research is not moving fast enough. Most
of those vaccines which have moved beyond
tests on animals and on to human testing, are
in or have completed only the first phase of
testing. These tests involve a very small num
ber of people to ensure safety, without any re
sults regarding effectiveness.
The good news is that one vaccine is ready
to begin a later phase of testing, which will in
clude people who were at high risk of getting
infected with HFV, and therefore will look not
only at whether they are safe, but also whether
they are effective at preventing infection. The
individuals involved are ftom HIVNET which
recruits high-risk people, tries to teach safer
behavior and also enrolls people into preven
tive trials. The vaccine is c^ed ALYAC (from
the fret it was designed in Albany, NY: “ALbany
YACcine”). It will be tested in 14 sites across
the country, involving 420 people. One-third
of them will receive a placebo, one-third will
get the ALYAC and one-third will get the
ALYAC plus another vaccine known as GP-120
(which uses the non-active outer coating of the
virus.) However, because infection rates are not
that high in this country, the trial will take three
years to complete, and it still isn’t large enough
to determine whether the vaccine works. If the
results of this trial look promising, then a much
larger and perhaps longer trial will be needed.
Meanwhile, there are numerous other vaccines
that have not had even the early safety tests,
and many more which have had that first phase,
but have not been approved for further testing.
A number of activists are frustrated at the
slow response. To move the development of
some HIY treatments, the tests after the initial
safety tests are often rolled into one. Some ac
tivists believe something similar should be done
for preventive AIDS vaccine trials. Individuals
wisffing to promote the development of a pre
ventive vaccine may want to attend the National
AIDS Yaccine Advocacy Forum to be held in
San Diego, CA this November. For informa
tion, call the AIDS Yaccine Advocacy Coali
tion at (415) 248-1330.
A critical concern
While there is optimism about the possibil
ity of developing a vaccine, there are also con
cerns. It will be years before any vaccine could
be available and it may be much less than 100
percent effective. One of the questions that
experts are struggling with is what the impact
would be if there was a vaccine that lowered
one’s chances of getting the disease by 70 per
cent or 90 percent but didnt completely pro
tect an individual. Given that possibility, a vac
cine will be an added layer of proteertion, not
an alternative to current prevention methods.
While there is testing of potential vaccines,
no vaccine to date has been built which will
stop the illness. It needs to be understood that
practicing prevention through abstinence or
safer sex should still be viewed as absolutely
necessary. Even HIY-positive individuals need
to protect themselves as well as their parmers.
HIY is not the only disease that is transmitted
sexually and people with weaker immune sys
tems face higher risks. In addition, there is the
chance that one may contract a strain of the
virus which is resistant to some antiviral drugs.
Also, having a vital load which is undetectable
does not mean that the virus cannot be trans
mitted. Yaccine or no vaccine — safe practices
and protection are essential! ▼