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Acquired Immunodeficiency Syndrome: Meeting of the WHO
Collaborating Centres on AIDS
Following a consultation on acquired immunodeficiency syndrome
(AIDS) in April 1985, the World Health Organization (WHO)
established
a network of Collaborating Centres on AIDS to provide a framework
for
international cooperation, including training, provision of
reference
reagents, evaluation of methods, and epidemiologic surveillance
(1).
The directors of the WHO Collaborating Centres, together with other
experts in virology and public health, met in Geneva, Switzerland,
September 25-26, 1985, to make recommendations for WHO's 1986-1987
international activities on AIDS.
Participants at the meeting reviewed the epidemiologic status
of
AIDS and affirmed the disease was now a major public health problem
in
several countries of the developed and developing world. Over
13,000
AIDS cases were reported from 1981 to September 1985 in the United
States, and the number of reported cases will probably double in
1986. More than 2,000 cases have been reported from 40 other
countries. The Director-General of WHO expressed the great degree
of
concern felt in almost all 166 Member States of WHO regarding AIDS.
In the United States and western Europe, approximately 90% of
cases among adults continued to occur in homosexual and bisexual
men,
intravenous drug users, and sexual partners of persons in these
groups. Although it is expected that additional AIDS cases may
develop in recipients of blood and blood products who are already
infected with the causative virus of AIDS,
lymphadenopathy-associated
virus/human T-lymphotropic virus type III (LAV/HTLV-III), future
infections from blood and blood products can now virtually be
considered preventable by screening blood donations for evidence of
antibodies to the virus. Most pediatric cases of AIDS have
occurred
among children of persons in known risk groups. In several
developing
countries, however, most adult AIDS patients have been sexually
active
heterosexual men and women.
There is no evidence that LAV/HTLV-III is spread through casual
contact with an infected individual, such as contact in family
settings, schools, or other groups living or working together. The
risk of infection of health-care workers seems very remote. At
present, there is no evidence that blood-sucking insects transmit
the
disease.
The group concluded that an internationally accepted case
definition of AIDS, relevant to its most severe clinical
manifestations, was needed for surveillance purposes. For
therapeutic
trials or other research purposes, broader definitions may be
required.
In countries where appropriate technologies are available, the
surveillance definition for AIDS given by CDC and published by WHO
(2)
was endorsed by the group. Surveillance definitions are now being
developed for use in countries where access to diagnostic
techniques
is limited.
The group concurred on the following issues:
For routine, large-scale testing for AIDS, the only
practical
methods currently available involve tests for antibodies
to
LAV/HTLV-III.
All sera reactive for anti-LAV/HTLV-III antibody in a
radioimmunoassay (RIA) or enzyme-linked immunoabsorbent
assay
(ELISA) test should be confirmed by an independent test
system, e.g., by immunoprecipitation or immunoblot tests.
Assays for this antibody of higher specificity but lower
sensitivity than that of conventional commercial ELISAs
may
be more appropriate for seroepidemiologic studies where
confirmatory tests are not available.
Posttransfusion AIDS can be eliminated by excluding donors
from groups at increased risk of infection and by
screening
all units of blood for antibodies to LAV/HTLV-III.
Because
infection can be transmitted from women to babies during
the
perinatal period, women who are antibody-positive should
be
advised to avoid pregnancy.
Reusing unsterile needles carries with it the risk of
transmitting AIDS and other blood-borne infections. This
procedure should be strongly discouraged.
The possible transmission of infectious diseases through
the
use of jet injection devices was discussed. After
considering the available information, the group concluded
that there was no evidence of a risk of transmission of
blood-borne infection from using such devices.
Studies to identify effective therapeutic regimens for
AIDS
patients and work on developing vaccines are in progress
in
several countries. Successful therapy may require a
combination of antiviral agents and substances that
enhance
immune responsiveness. Passive protection against
infection
is being pursued experimentally, including the use of
monoclonal antibodies and hyperimmune gammaglobulin.
Further
work towards understanding the role of antibody in
preventing
and treating AIDS is required before these substances can
be
utilized in patients.
New antiviral drugs require careful study using the
procedures of classical drug-evaluation protocols, under
the
guidelines of national control authorities. Studies to
define the pharmacology, toxicity, and tolerated dosages
must
precede studies to determine the benefit.
Placebo-controlled studies in patients with mild forms of
disease due to LAV/HTLV-III infection should be
encouraged.
Such studies will yield an answer on the efficacy of a
drug
more quickly and with fewer patients than the use of
historic
controls.
The prevalence of AIDS will depend heavily on the success
of
risk-reduction programs based on public information and
education.
Because patients infected with LAV/HTLV-III often have
immune-function abnormalities, administration of the
commonly
used live-virus vaccines (e.g., polio, measles) to such
individuals could pose a theoretical risk. However, to
date,
no unexpected adverse reactions have been noted in
individuals with antibody to LAV/HTLV-III, and such
patients
are free of overt signs of clinical AIDS when given the
vaccines recommended by WHO for childhood or adult
immunization programs.
T-lymphotropic retroviruses of simians provide potentially
valuable models for studying the control and treatment of
AIDS (3).
An important aspect of WHO activities on AIDS will be the
collection of data on the incidence of the disease or its
causative virus by Member States and the WHO Collaborating
Centres and the regular transmission of this information
to
WHO headquarters. Wherever possible, information on the
gender, age, recognized risk factor (if any), and major
clinical features should also be provided
A full report of the meeting is available from the Director,
Division of Communicable Diseases, WHO, Geneva.
Adapted from WHO Weekly Epidemiological Record 1985;60:333-5.
References
WHO. Acquired immune deficiency syndrome (AIDS). WHO
consultation. Weekly Epidemiological Record 1985;60:129-30.
WHO. Acquired immune deficiency syndrome (AIDS). Revision of
the
case definition of AIDS. Weekly Epidemiological Record
1985;60:270-1.
WHO. T-lymphotropic retroviruses of non-human primates. WHO
informal meeting. Weekly Epidemiological Record
1985;60:269-70.
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