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De nombreuses études dont celle de Padian effectuée en 1997 démontrent que le risque transmission par rapport sexuel non protégé est infime de l'ordre de 1 pour 1000 et encore parfois on lit 1 pour 10000.

Je me demande si ces personnes étaient sous traitements arv car ils semblent que les traitements diminuraient les risques de transmissions alors qu'à l'inverse les personnes en séroconversion seraient extrémement contagieuse.

Qu'en pensez vous ?

Naturellement ce sujet est ouvert dans l'hypothèse où il y aurait bien un virus sexuellement transmissible.

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Il s'agit de personnes sans traitement.

Voici l'abstract :

Voici leur conclusion (le document complet n'est pas officiellement en ligne) :

In general, we estimate that infectivity for male-to-female transmission is low, approximately 0.0009 per
contact, and that infectivity for female-to-male transmission is even lower. While data from this study suggests
that the probability of male-to-female transmission appears to vary across couples, our estimate may still be useful
as an index of “average” transmission risk for the purpose of comparisons among studies, or in epidemic model
construction. Furthermore, our estimation procedure does not require knowledge of the infection time of the index
case, which is usually unknown in partner studies; estimation procedures that fail to take this uncertainty into account
are potentially subject to serious biases (12). While our estimation procedure does not require that infection
time be observed, it does depend on the assumptions of constant contact rates and parametric forms for the infectivity.
(We assumed that the infectivity was either constant, linearly increasing, or linearly decreasing with time following
index case infection.) Direct nonparametric estimation of this quantity is problematic in the absence of information
on when the index case became infected (9).
Currently identified risk factors remain imprecise predictors of transmission. Two infected men whose
female partners had all of the risk factors that we found to be significant in this study did not transmit the disease.
Fewer than 50 percent of such couples with three of the risk factors had transmission events. In contrast, five
women with no identified risk factors acquired HIV from their male partners. While some of these results might be
attributed to errors in self- report, other factors which affect infectiousness and/or susceptibility may remain to be
identified. As with studies of long-term survivors of HIV infection (28), an obvious area for future investigations is
to focus on immunologic, genetic, and virologic factors among those individuals with multiple risk factors for
whom transmission did not occur, compared with couples where transmission occurred in the absence of known
risk factors.
While lack of transmission in our prospective study may in part be due to such unidentified protective factors,
we also observed significant behavior change over time. In previous reports (8, 14, 29), the proportion of
couples who used condoms at their last follow-up prior to analysis was 100 percent; the 75 percent reported here is
the lowest proportion that we have observed. The proportion of couples who would use condoms if the study were
continued beyond 10 years remains unknown. Nevertheless absence of seroincident infection over the course of the
study cannot be entirely attributed to significant behavior change. No transmission occurred among the 25 percent
of couples who did not use condoms consistently at their last follow-up nor among the 47 couples who intermittently
practiced unsafe sex during the entire duration of follow-up. This evidence also arguged for low infectivity in
the absence of either needle sharing and/or cofactors such as concurrent STDs.
Because couples were recruited on a volunteer basis, results presented here are not necessarily reflective of
trends in the population. Nevertheless, the increase over time in the recruitment of number of couples where the
index case was an injection drug user or was infected from a previous heterosexual partner, as well as the increase
in recruitment of minority couples may reflect the changing nature of the epidemic in Northern California as infection
spreads outside homosexual and bisexual communities. The results from our study, including both the characteristics
of participants and observed risk factors for transmission, confirm the significant contribution of both injection
drug use and infection with other sexually transmitted diseases.

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