Part II: Sexual Transmission and
Note: This is Part II in a
2--part series on the Domestic HIV Epidemic. You can read Part I
Although most people
today understand that hugging an HIV-positive person will not put
them at risk, many still have misconceptions about transmission in
the bedroom. One important myth to dispel is that women frequently
act as agents of transmission. In fact, research shows that HIV in
the United States is overwhelmingly transmitted from men to other
men and from men to women. This is because it is much more difficult
for women to infect men or other women than it is for men to infect
their sexual partners. Women simply don’t typically release
emissions that carry high viral loads. Yes, it’s possible for a
woman to infect a man or another woman during sexual intercourse.
But is it very likely? No.
The fact of the matter is
that HIV is most easily transmitted sexually via anal intercourse
from the penetrator to the penetrated. This is because the lining of
the rectum is one cell thick while the lining of the vaginal wall is
considerably thicker. Thus, tearing occurs much more easily during
anal intercourse – especially without lubricant. These tears are
prime sites for the virus to infiltrate the human body. Coupled with
this is the greater presence of lymphoid tissue in the rectum versus
the vagina. This tissue is a vital pathway into the body for HIV.
Without it, the virus would have a much more difficult time
successfully infecting its target. Thus, more passionate or
aggressive penetration isn’t the only factor that makes for risky
anal intercourse. The virus can be (and often is) transmitted
through vaginal intercourse. But human anatomy makes anal
intercourse more risky.
Some of the most
surprising data on HIV transmission concerns the difficulty of
becoming infected during certain sexual activities. Even the
highest-risk sexual behavior carries a relatively low probability of
transmission. For HIV-negative receptive partners during unprotected
anal sex with known positive partners, there is about a 1 in 120
change of becoming infected. For HIV-negative “tops,” the risk
unprotected anal sex per encounter with an HIV-positive bottom is
about 1 in 1,600. While these per-encounter risks are relatively
low, the aggregate annual risk that an average person encounters is
significantly higher. It’s important to keep in mind, however, that
these data are for sexual encounters with known HIV-positive
partners. The risks for transmission during encounters with partners
of unknown HIV status are lower.
The most confusion,
however, typically surrounds oral sex. Different people will come to
different conclusions on whether oral sex poses a risk for
transmission. The answers vary because the issue is complex. The
human mouth is a very inhospitable place to the virus. Enzymes in
saliva readily inactivate the virus, and any ejaculate that finds
its way to your stomach will be destroyed by stomach acid (though
HIV has been isolated from saliva in the laboratory, this is
extremely rare and not very probable). However, at any given moment
your mouth has a number of small cuts that could act as potential
infection sites. For the virus to find its way from the penis to
such a cut, though, it must survive the numerous obstacles within
the mouth. For this to happen without taking ejaculate into the
mouth, it would almost certainly take a male partner with an
extremely high viral load. However, it must be pointed out that even
when ejaculate is taken into the mouth, the risk of becoming
infected from a positive partner is relatively low. For example, the
per-incidence risk of a “giving” male partner becoming infected from
an HIV-positive “receiving” male partner is about 1 in 2,500. The
risk for oral sex performed on a positive female partner is even
These statistics can be
complicated by other factors, however. Though the virus can be
transmitted during sexual intercourse, HIV outside the body is
fairly innocuous. I could pour a vial of the virus over my healthy
fingers without worrying about becoming infected. The problems occur
when wounds and other lesions disrupt the skin. This is part of the
reason why the risk of HIV transmission increases in the presence of
another sexually transmitted disease – especially syphilis, a
bacterial disease that causes open sores ripe for HIV infection.
Health officials pay close attention to even minor outbreaks of
syphilis for precisely this reason; they can easily lead to an
increase of new HIV infections.
Seroconversion and Viral
When discussing HIV infection, scientists use the word
“seroconversion” to describe the moment when the body begins to
produce HIV antibodies. When a person seroconverts, their viral load
increases rapidly and peaks at a level higher than what remains for
the majority of the person’s life. This high of a viral load is not
seen again in the course of the infection until the last period of
infection called Full Blown AIDS, which often precedes death.
Exposure to a single
instance of the virus is not enough to infect a healthy individual.
Over the course of evolution, the human body has developed immune
responses and protections that combat a certain level of viral
infection. Studies show that a critical viral mass of HIV is needed
to infect a healthy person. In other words, if a positive person
with a viral load below that critical number has sexual intercourse
with a negative person, the risk of infection drops dramatically
below what it would be if their viral load exceeded that level.
Thus, many researchers believe that new HIV infections are on the
decline in certain communities because of protease inhibitors (a
main component of medication for people living with HIV) that are
able to decrease viral loads, often to undetectable levels. It
becomes more difficult for the virus to spread when these powerful
drugs keep its numbers in check.
This is important when
thinking about how HIV spreads. If high viral loads dramatically
increase transmission rates, then it would seem that those two
points during the HIV infection with the highest viral loads would
be the times that the virus is most easily transmitted. While this
is technically true, it isn’t practically useful information. This
is due to the fact that when a person’s viral loads are so high, the
body reacts with a powerful immune response. This experience is
something similar to an acute flu infection. In short, it wipes you
out. People often say that HIV has no symptoms at first – but this
isn’t entirely true. It’s just that the initial flu-like infection
(which lasts for a few days) is often mistaken for an actual flu
infection. Thus, the moment that HIV-positive people are the most
likely to infect others is the moment when they’re experiencing
these unpleasant symptoms. This may cause some concern for IV-drug
transmission, but it’s doubtful that one would be interested in
having sex when one can barely get out of bed.
During the course of a
“normal” HIV infection, the viral load follows somewhat of a
pattern, as described above. However, other STDs complicate matters.
As mentioned previously, STDs that cause open sores are an important
factor for increased transmission risk, but this isn’t the whole
story. The other reason lies in the increased viral loads of HIV in
people infected with other STDs. HIV-positive people who are
simultaneously infected with another STD carry higher viral loads
than those without other infections. This is yet another important
reason for vigilance when monitoring STD outbreaks other than HIV.
New scientific studies are
also revealing that drug use can increase viral loads as well, and
may even speed up the course of the HIV infection.
A Call for Informed
No one seems to be interested in discussing the reality of the HIV
epidemic in the United States. Images of African countries being
ravaged and freak cases of infection by nontraditional methods
dominate our understanding of the disease. While it is important for
the United States to help tackle the debilitating epidemic in other
countries, it is equally important for us to understand the epidemic
in our own country. Moreover, within our community much of what we
hear is from alleged “safe sex” campaigns that often do more to
scare queer men away from sex than to encourage them to play safely.
Healthy sex campaigns must be sex-positive and must be founded on
solid data and scientific knowledge, or we can expect to see more
panic and side effects such as the “bug chasers.”
I want to stress the fact
that I am not interested in promoting unsafe sex – consistent condom
use is vital to keeping HIV on the decline. Heavy drug use (namely
crystal methamphetamine) and the subsequent risky sexual behavior
some men are engaging in are threatening to destroy the progress our
community has made toward eliminating the virus from the community.
I do no want to belittle the threat that HIV poses to our community.
That said, I am interested in the facts – specifically those that
aren’t being discussed. No one seems interested in telling you that
if you use protection consistently, regularly get tested for HIV and
other STDs, and communicate honestly and openly with your sexual
partners, there is no reason why you cannot lead an active sexual
life free from fear of contracting HIV. Can condoms break? Yes. Can
the virus be transmitted during oral sex? Yes. But the gap between
possibility and probability has been skewed, and when dealing with a
virus like HIV, we cannot afford to wallow in ignorance.
Editor’s Note: Trevor
Hoppe is a senior Political Science major and Sexuality Studies
minor. He would like to thank Professor David Halperin from the
University of Michigan for assistance with this article.