Role of the primary infection in epidemics of HIV infection in gay cohorts.

摘要: A review of the data on infectivity per contact for transmission HIV suggests that may be order 0.1-0.3 anal intercourse in period initial infection, 10(-4) to 10(-3) long asymptomatic period, and 10(-2) leading into AIDS. The pattern high contagiousness during primary infection followed by a large drop infectiousness explain epidemic spread seen male homosexual cohorts early years epidemic. Simulations males, using range parameter values, indicate following: (a) fast rise then more or less rapid flattening incidence curve seropositives is primarily due spread, yielding group infecteds all whom pass low at close same time. All this occurs only if basic reproduction number > 1. (b) behavioral changes have been reported started after new infections began fall, too late major effect rise. had slowing down subsequent seropositives. (c) High activity groups play an important role However, it not likely decrease rate growth solely saturation these very groups. Although evidence interpretation conclusive, its implications prevention vaccine trials are so markedly different from those other interpretations we consider hypothesis further testing.