AEGiS-13IAC: Effectiveness of potent anti-retroviral therapies on reducing perinatal transmission of HIV-1.

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

Effectiveness of potent anti-retroviral therapies on reducing perinatal transmission of HIV-1.

Int Conf AIDS 2000 Jul 9-14; 13:17 (abstract no.. LbOr4)

Blattner W, Cooper E, Charurat M, Thompson B, Hanson C, Mofenson L, Pitt J, Handelsman E, Diaz C, Hayani K, Smeriglio V, Hoff R
Institute of Human Virology, Baltimore, MD 21202. Fax: 410 706-1944, E-mail: blattner@umbi.umd.edu.

OBJECTIVE: The WITS, a prospective clinical cohort study, has followed pregnant women with HIV-1 infection since 1989 through time periods characterized by different therapies. The current study evaluates the impact of different therapeutic strategies on viral load at delivery and perinatal transmission. Design: Plasma HIV-1 RNA were serially measured in 1482 women who had singleton delivery from 1/90-9/99. The risks of transmission were analyzed in relation to maternal viral loads, other maternal and obstetrical covariates by logistic regression.

RESULTS: The transmission rates were as follows: 20.7% for 381 untreated women; 19.4% for 206 women on ZDV monotherapy before the PHS recommendation (<4/94); 7.7% for 530 women on ZDV monotherapy after 4/94; 3.9% for 179 women on combination therapy without protease inhibitors; and 1.1% for 186 women receiving HAART. This relationship remained after calculating adjusted rates using logistic regression that included model covariates that defined high risk pregnancies. Transmission rates increased with increasing viral loads at delivery. Specifically; 0.9% for undetectable (<400 copies); 6.4% for 400-3K copies; 11.3% for 3K-40K copies; 21.1% for 40K-100K copies; and 30.1% for >100K copies. Within each delivery-viral load stratum, there was an ordinal response between transmission and increasingly complex therapies. There were 2 women with viral loads less than 400 at delivery who transmitted, one received HAART for one month before delivery but was taking illicit drugs during pregnancy; the other received combination therapy but also had a duration of membrane rupture greater than 24 hours.

CONCLUSIONS: There was an independent protective effect of anti-retroviral agents on prevention of HIV-1 transmission regardless of viral load levels at delivery. This effect increased with therapies that included more complex drug regimens (HAART>Combination therapy>ZDV Monotherapy>None).

Keywords: AEGIS, HIV-1, Viral Load, Zidovudine, HIV Infections, Delivery, Obstetric, HIV-1 Reverse Transcriptase, Antiretroviral Therapy, Highly Active, Antiviral Agents, Prospective Studies, Human, Female, Pregnancy, transmission, surgery, therapy, drug therapy, AIDS
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