years after a much-heralded HIV test uncovered an outbreak
among black male college students in North Carolina, the
test is still not being widely used--a delay some
experts blame on government foot-dragging.
Government officials said they are not yet
endorsing the test because more studies need to be
conducted before they are convinced of its
effectiveness. The Centers for Disease Control and
Prevention announced plans this week to study the
test, called NAAT, in two upcoming trials. "The
questions are hard questions. The only way to answer them is
to evaluate it," said Bernard Branson, associate
director for lab diagnostics for the CDC's National
Center for HIV, STD, and TB Prevention.
NAAT--Nucleic Acid Amplification Test--provides
a new weapon for HIV experts. It was the main reason
North Carolina health officials, who developed the
test, were able to uncover an outbreak of the AIDS virus
among 84 students at 37 colleges in the state. Conventional
tests hunt for HIV by looking for antibodies. But
these can take weeks to develop in the bloodstream,
meaning a recently infected person would test negative.
The NAAT test, by contrast, finds the actual virus itself
and can do so within a week after infection.
Because the test is expensive, it is done using
blood pooling: Up to 100 samples that tested negative
using antibody tests are pooled together and tested at
once. If the virus is not found in the pooled sample,
officials go no further. If the virus is found,
individual samples are tested until the positive match
is found. NAAT has increased HIV detection by 4% in
North Carolina and 8% in San Francisco, where it has been
used since 2003. Nonetheless, few places use the test,
mainly because many health officials are waiting for
the CDC to endorse it.
Some experts said the time to use the test is
now. "We can't wait for the CDC to do anything--it's
up to localities to take the initiative," said Jeffrey
Klausner, San Francisco's director of sexually
transmitted disease prevention. "I would love to see strong
evidence, but we often have to act and implement control
efforts before we have the highest level of evidence."