Current Trends Human T-Lymphotropic Virus Type III/
Lymphadenopathy-Associated Virus Antibody Testing at Alternate
Sites
On March 2, 1985, an enzyme-linked immunosorbant assay (ELISA)
test to detect antibodies to human T-lymphotropic virus type
III/lymphadenopathy-associated virus (HTLV-III/LAV) was licensed by
the U.S. Food and Drug Administration to screen blood and plasma
collected for transfusion or manufactured into other products.
Since
it was recognized that many individuals in groups at high risk for
AIDS might want testing to determine their antibody status, federal
funds for alternate testing sites were made available so that
HTLV-III/LAV antibody tests could be obtained free of charge
outside
the blood-bank setting. A primary goal was to protect the nation's
blood supply by limiting the potential for donation of
false-negative
units. The alternate sites were also needed to ensure that
individuals wishing to be tested would receive appropriate pretest
counseling, post-test counseling, and referral for medical
evaluation,
if indicated.
Cooperative agreements between CDC and 55 state and local
health
departments began April 26, 1985. The cooperative agreements were
for
a 90-day period, since they were intended to defray start-up costs
only. Most agreements were subsequently extended for an additional
90
days without additional funding at the request of the individual
health departments. Preliminary data on the activities supported
by
the cooperative agreements were reported to CDC in September 1985
and
January 1986. As of September 6, 1985, at least one alternate
testing
site had been established by 52 of the 55 project areas; an
estimated
518 sites had been established nationwide; and 21,200 persons had
been
tested.
Activities increased substantially during the last quarter of
1985. By December 31, 1985, 874 testing sites had been established
in
53 project areas (Table 5). This total included 275 sites in New
York
City located in private physicians' offices. Nationwide, 79,100
persons had been tested. Pretest counseling had been provided to
93,900 persons, and post-test counseling, to 55,500. A total of
17.3%
of the individuals tested at these sites had repeatedly reactive
ELISA
tests. No relationship was noted between the number of acquired
immunodeficiency syndrome (AIDS) cases reported in a particular
project area and the number of tests performed at alternate sites
(Table 6).
Reported by Div of Sexually Transmitted Diseases, Center for
Prevention Svcs, CDC.
Editorial Note
Editorial Note: Many of the project areas reported they had
underestimated the difficulty of establishing alternate sites on a
short-term basis. Start-up delays were common because of
administrative procedures and such factors as general hiring
freezes
and the development of systems to assure strict confidentiality of
all
records related to counseling and clinical laboratory test results.
Moreover, the initial demand for services was less than most areas
had
anticipated. The number of tests performed in each area depended
on
many factors, including accessibility of services, perception of
the
benefits or risks of testing, and awareness of the existence of
services by those at risk. The utilization of the sites varied
widely
in both high and low AIDS-incidence areas (Table 6), perhaps
indicating that demand for testing depends on the degree to which
it
is encouraged and made accessible for persons at risk. In one
project
area with a high test-to-case ratio, testing was actively promoted
by
both public health authorities and AIDS risk-group representatives
(1).
The goal of protecting the blood supply by providing alternate
sites at which persons could be tested was achieved. In addition,
experience with the HTLV-III/LAV ELISA tests since licensure in
March
1985 has shown them to be remarkably sensitive and specific (2) and
to
be useful, not only for preventive purposes, but also for the
diagnosis and differential diagnosis of clinical illness. An
evaluation of the tests used to screen blood donors in a large
metropolitan area showed a specificity of 99.8% (3). Thus, they
have
value in identifying individuals who are infected, and who are
likely
to be able to transmit the infection to others by the established
routes of transmission, even if such individuals themselves are
asymptomatic.
Accordingly, the U.S. Public Health Service has proposed
additional applications to prevent perinatal transmission (4) and
to
help reduce drug abuse-related and sexual transmission of
HTLV-III/LAV
virus by infected persons (5). The main purpose of the additional
applications is to facilitate identification of seropositive
asymptomatic persons, both for medical evaluation and for
counseling
to prevent transmission. Reduction of sexual and drug-related
transmission of HTLV-III/LAV should be enhanced by using available
serologic tests to give asymptomatic, infected individuals in
high-risk groups the opportunity to know their status so they can
take
appropriate steps to prevent further transmission (6).
The wide network of alternate testing sites that has been
established by state and local health departments, frequently in
cooperation with local community groups, may facilitate extension
of
testing services to selected populations at increased risk for
HTLV-III/LAV infection.
References
Judson FN. Personal communication.
CDC. Update: Public Health Service Workshop on Human
T-Lymphotropic Virus Type III Antibody Testing--United States.
MMWR 1985;34:477-8.
Ward JW, Grindon AJ, Fiorino PM. Laboratory and
epidemiological
evaluation of an enzyme immunoassay for antibodies to human
T-lymphotropic virus, type III. JAMA (in press).
CDC. Recommendations for assisting in the prevention of
perinatal
transmission of human T-lymphotropic virus type
III/lymphadenopathy-associated virus and acquired
immunodeficiency
syndrome. MMWR 1985;34:721-6, 731-2.
CDC. Additional recommendations to reduce sexual and drug
abuse-related transmission of human T-lymphotropic virus type
III/lymphadenopathy-associated virus. MMWR 1986;35:152-5.
Handsfield HH, Dunphy CA, Bonin P. Unpublished data.
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