EDITORIAL COMMENT: This paper was accepted for publication to update readers on the effectiveness of treatment with zidovudine to prevent vertical transmission (mother to child by any route before or after delivery) of HIV infection antenatally. In the ACTG 076 trial referred to in this paper the treatment regimen was antepartum zidovudine (ZDV) (100 mg orally 5 times a day) initiated between 14 and 34 weeks' gestation and continued throughout the remainder of pregnancy, followed by intrapartum intravenous ZDV (loading dose 2 mg/kg, starting in labour followed by continuous infusion 1 mg/kg/hour until delivery), followed by oral administration of ZDV (syrup 2 mg/kg every 6 hours for 6 weeks beginning 8 to 12 hours after birth) to the infant. HIV infection of the infant was defined by 1 positive viral culture obtained from peripheral blood specimens taken at birth, 12, 24 and 78 weeks postpartum. Preliminary results showed HIV infection (at least 1 positive culture) in 7.2% (13 of 180) in the treatment group and 21.7% (40 of 184) in the untreated control group. The present study suggests that a less complex ZDV regimen is effective against vertical transmission since no evidence of HIV infection was found in any of the 50 infants within 48 hours of birth. The authors properly comment that these infants require follow-up to assess intrapartum and postpartum transmission of HIV, and long-term side-effects of the ZDV treatment.

Summary: In Thailand, the prevalence of paediatric HIV-1 infection has increased rapidly through vertical transmission. According to the ACTG 076 trial regimen, zidovudine treatment in HIV-infected pregnancy can reduce vertical transmission. However, this treatment is complex and costly. It is not applicable for developing countries. We conducted a study to evaluate the effect of zidovudine treatment in late pregnancy on HIV-1 in utero transmission. Fifty cases of asymptomatic HFV-1 infected-women were voluntarily enrolled to the study. Zidovudine 250 mg orally twice a day was given to these patients from gestational age 36 weeks until labour. The newborns were evaluated at birth by a neonatologist and peripheral blood was tested for HIV genome by PCR technique within 48 hours of birth. The study revealed that no HIV genome was detected from the peripheral blood of newborns. It is suggested that zidovudine treatment in late pregnancy could reduce HIV-1 in utero transmission.