Vertical Transmission Often Occurs In Utero, Zimbabwe Study Finds
Vertical transmission of HIV in Zimbabwe often occurs in utero rather than in the intrapartum period, a study published in the Dec. 15 Journal of Acquired Immune Deficiency Syndromes shows. Reuters Health reports that the WHO study performed in Zimbabwe between 1992 and 1995 examined the timing of HIV transmissions from woman to fetus in 42 HIV-positive women, and did not include any antiretroviral drugs. Dr. David Katzenstein from Stanford University Medical Center, one of the study's authors, said that the "most striking finding" from the research was the "high frequency of in utero transmission or apparent in utero transmission" among study subjects. Researchers found HIV RNA in 90% of the maternal plasma samples and "relatively high levels of closely related viral RNA" in 38% of paired cord samples. "This indicates that a high percentage of these babies are at least exposed to [a] virus similar to their mother's even before they are born," Katzenstein said. Katzenstein added that researchers "still don't completely understand" the reasons for the high in utero transmission rate. He stated that he and other scientists are now launching pilot studies in Zimbabwe using single-dose nevirapine and AZT to examine whether these drugs interrupt in utero transmission. But Katzenstein noted that if HIV is transmitted during the in utero period, "a single dose of nevirapine is not likely to prevent infection of the infant." Anticipating opposition from the Zimbabwean government, Katzenstein added that the team will "have to push them as hard as we can to try to get them to use antiretroviral therapy in this context" (Reuters Health, 1/12).
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