BALTIMORE--A small study of HIV-infected patients conducted by
researchers at the National Institute of Allergy and Infectious
Disease (NIAID) shows that inoculation with a common vaccine can
temporarily increase the amount of HIV that is circulating in
All 13 of the HIV-positive subjects who received a tetanus shot
as part of the experiment showed increased viremia after their
inoculation, NIAID director Anthony S. Fauci said at the American
Association for the Advancement of Science (AAAS) meeting.
He cautioned, however, that the finding is too preliminary to
make any recommendations regarding whether to limit vaccinations
for people infected with HIV. However, based on his experience
treating AIDS patients, Dr. Fauci said he would "rather have
a patient with a small blip in HIV levels from a needed inoculation
than with a full-blown infectious disease."
A long-standing question among AIDS researchers is whether persistent
infections or co-infections can increase the risk of HIV infection
and/or hasten the time to development of full-blown AIDS. Dr.
Fauci cited as an example the case of a person whose HIV blood
levels rose after he developed tuberculosis and dropped again
after he responded to treatment for the disease.
The NIAID vaccination experiment grew out of a study of the role
of cyto-kines in immunity and their influence on HIV. Among HIV-infected
individuals, there occurs "a hyperexpression of cytokines"
because the virus releases factors that can stimulate cytokine
production, Dr. Fauci said.
Different cytokines can upregulate or downregulate the AIDS virus.
Most, however, act to increase the burden of HIV in the blood,
while immune system CD8 cells suppress HIV expression.
"Going on in the body virtually every minute is this tug-of-war
between the upregulating and downregulating factors," he