Document 2529
 DOCN  M94A2529
 TI    The effect of a transient period with high risk contacts on the dynamics
       of the HIV epidemic.
 DT    9412
 AU    Wittkowski KM; Hasan M; Dept. Med. Biometry, Univ. Tubingen, Germany.
 SO    Int Conf AIDS. 1994 Aug 7-12;10(1):283 (abstract no. PC0053). Unique
       Identifier : AIDSLINE ICA10/94370046
 AB    OBJECTIVE: In Arab countries, the low reported AIDS incidence--even when
       adjusted for under reporting--might lead to the impression that 'the
       West has condoms, we have the Quran'. We discuss how different
       traditions regarding sexual behaviour among young adults may affect the
       spread of HIV. METHODS: HIV is assumed to spread from a core-group
       (highly promiscuous homosexual men) via a high-risk group
       (homo-/bisexual men, injecting drug users) and heterosexual partners to
       low-risk heterosexuals. The parameters of this model (size of
       sub-populations, behavioural changes, contact rates) are fitted against
       back-calculation estimates for HIV incidence in Germany based on
       reported, delay-corrected AIDS cases. The results are compared with a
       model, where the higher-risk groups are smaller and have lower contact
       rates, while behavioural changes are less effective and 5 percent of the
       heterosexuals have a 5-year period with high risk (e.g. anal) contacts
       before entering the low risk population. RESULTS: In western countries,
       HIV incidence among high-risk groups and their heterosexual partners
       peaked in 1983-85 and 1987-1989, respectively. Because here the basic
       reproduction number among heterosexuals can only minimally exceed the
       critical value of 1, HIV incidence will remain well below 1/100,000 per
       year for the next few decades, although it may increase thereafter.
       Where a transient period of high-risk behaviour cannot be excluded,
       however, HIV can spread much faster into the heterosexual population,
       and the incidence may reach 3/100,000 among low-risk heterosexuals per
       year (and the prevalence 30/100,000) by the year 2000, even if only
       relatively few high-risk persons are infected. DISCUSSION AND
       CONCLUSIONS: A transient period of high-risk behaviour may facilitate
       the spread of HIV for two reasons. First, even 5 percent of the
       population are a huge pool for the virus and the short duration hinders
       saturation. Second, transport (at the end of the transient period) is
       more effective than transmission (through heterosexual contact). That no
       peak in incidence among high-risk groups has been observed until now in
       Arab countries, must not be mistaken as an indication that HIV is
       spreading as slowly among heterosexuals as in western countries.
 DE    Germany/EPIDEMIOLOGY  Human  HIV Infections/*EPIDEMIOLOGY/TRANSMISSION
       Male  Middle East/EPIDEMIOLOGY  Risk Factors  Sex Behavior  MEETING
       ABSTRACT

       SOURCE: National Library of Medicine.  NOTICE: This material may be
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