| A
New Attempt to Solve one of AIDS's Biggest Riddles |
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On Jan. 17,
researchers will propose that the National Institutes of Health support
an international study to determine the best time for patients to start
highly active antiretroviral therapy (HAART). The trial would involve
9,000 participants randomly assigned to two treatment groups, either
immediate HAART or HAART in response to the weakening of the immune
system.
"Universally, people feel this is an important question," said Dr.
Anthony S. Fauci, head of the National Institute of Allergy and
Infectious Diseases, which will consider the request.
No one is certain when the tradeoff between quality of life, cost,
self-image, potential adherence burden or adverse affects from long-term
HAART start to tip toward the life and health advantages of initiating
HAART. Researchers have known for years to begin HAART at least by the
time a patient's CD4 lymphocytes fall to 200 per microliter of blood,
below which patient mortality rates increase.
But at what point
above 200 should HAART begin? The US government and World Health
Organization recommend HAART when a patient's CD4 count falls between
350-200. Some doctors believe HAART may best be started at 500. A
healthy CD4 count is approximately 750.
In the international study proposed, patients with CD4 counts over 500
would randomly begin HAART either immediately or wait until the counts
were 300-350. The second arm would enroll patients with lower CD4 counts
and randomly assign them to immediate HAART or wait until counts were
200-250.
Now that newer
HIV drugs come in simpler dosing schedules, have fewer
side effects, can be combined in hundreds of regimens, and are not
likely to improve much in the near future, it has become more imperative
to answer the question of when to initiate HAART.
Washington Post
(01.07.07):: David Brown |
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| We are providing the above information as a public
service only. Providing synopses of key scientific articles and lay
media reports on HIV/AIDS, other sexually transmitted diseases
does not constitute endorsement. The above summaries were prepared
without conducting any additional research or investigation into the
facts and statements made in the articles being summarized, and
therefore readers are expressly cautioned against relying on the
validity or invalidity of any statements made in these summaries. This
CDC HIV/STD/TB Prevention News
Update also includes information from CDC and
other government agencies, such as background on MMWR articles, fact
sheets and announcements. |
| HIV1 - ELISA
Antibodies |
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Most people
infected with HIV carry the virus for years before manifesting AIDS.
During that period, infected people will have few, if any, symptoms yet
they can transmit the virus.
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The
percentage of women with AIDS has increased steadily, and the percentage
of people infected heterosexually has also increased, surpassing the percentage
infected through injecting drug use.
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During 2001, there were 35575 newly diagnosed cases of HIV infection.
The Centers of Disease Control and Prevention (CDC) estimates
now
that 40,000 new cases of HIV transmission occur every year.
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Of
the people infected with the virus of AIDS in the USA in the year 2001, 42%
were whites, 37% blacks, 20% Hispanics and <1% Asians and Pacific
Islanders and <1% American Indians and Alaska Natives.
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During the 1990s, the HIV epidemic shifted steadily toward a growing
proportion of AIDS cases in blacks and Hispanics and in women.
Human Immunodeficiency Virus
(HIV) is the cause of AIDS (Acquired
Immuno
Deficiency Syndrome).
The presence of HIV in the body can be detected in several ways. The
most common is the HIV-ELISA Antibodies test.
The
HIV-ELISA
looks for the body
response to the virus
manifested by the
presence in your blood of
Antibodies
to HIV proteins. Antibodies are special proteins that our Immune System
produce in response to the presence of HIV.
The test performed on your
sample actually consists
of two tests: a Screening test and a Confirmatory test. The
screening test procedure is called an
ELISA—Enzyme Linked Immuno-Sorbent Assay
or an EIA (Enzyme Immunosorbent Assay). The
confirmatory test is used in the event your HIV-ELISA is positive and/or
equivocal and is the procedure used is the Western
Blot Assay (WB)
The screening and
confirmatory tests are usually done using small samples of blood. If a
sample of blood tests positive repeatedly in the screening test, it will be
confirmed through the Western Blot test. People will be informed that they are infected
with HIV only after both the screening and confirmatory tests
have shown a positive (reactive) result.
Positive HIV antibody tests results
are over 99% accurate when confirmed. Negative HIV antibody tests are over
99% accurate if it has been at least six months after a contact with a
potentially HIV-infected partner. False negatives or false positives occur
rarely.
Antibodies to HIV can be
detected in the blood, in the urine or in the saliva. People produce
antibodies with different speeds and therefore the time interval between
infection and the development of antibodies to HIV can go from four weeks
to six months from the exposure date or SDC (
Suspected
Date
of
Contact).
The appearance of antibodies in a blood or urine sample of a person which
was known to be negative to HIV is called
Seroconversion.
The HIV Elisa results are usually available in one or two business days.
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