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Thai Red Cross zidovudine donation program to prevent vertical transmission of HIV: the effect of the modified ACTG 076 regimen

Thisyakorn, Usaa,b; Khongphatthanayothin, Manaa; Sirivichayakul, Suneea; Rongkavilit, Chokechaia; Poolcharoen, Wiputc; Kunanusont, Chaiyosc; Bien, Darl D.d; Phanuphak, Praphana,b

Epidemiology & Social

Objectives: To evaluate the impact of the modified ACTG 076 zidovudine regimen on the risk for vertical HIV transmission.

Design: Observational retrospective evaluation of a prospective cohort.

Setting: Thai Red Cross zidovudine donation program to reduce vertical HIV transmission.

Patients: HIV-infected Thai women and their offspring.

Intervention: The modified regimen consisted of 500 mg zidovudine daily during pregnancy and 300 mg zidovudine every 3 h during labor, taken orally, and 2 mg/kg zidovudine syrup four times daily for 6 weeks to infants.

Main outcome measures: Only infants with at least 1 HIV DNA polymerase chain reaction (PCR) result at age ≥ 4 weeks were included. HIV infection was defined by having at least one positive PCR at age ≥ 4 weeks. The transmission rate was calculated. Characteristics of women who did and did not transmit HIV to infants were compared.

Results: A total of 2891 women and their infants participated in the program and 726 infants of 719 women were included in the analysis. Forty-three infants were infected. The overall transmission rate was 6.0% (95% confidence interval, 4.4–8.0). There were no differences in maternal characteristics between transmitters and non-transmitters. The transmission rate in women who started zidovudine before 30 weeks’ gestation was not significantly different from that in women who started zidovudine at or after 30 weeks’ gestation: 5.7 versus 3.3%, respectively.

Conclusions: This modified zidovudine regimen is effective in reducing vertical transmission in a country with predominant subtype E infection. A donation program for preventing vertical HIV transmission can be implemented in developing countries, as in Thailand.

From the aThai Red Cross AIDS Research Centre, Thai Red Cross Society, Bangkok, the bFaculty of Medicine, Chulalongkorn University, Bangkok, the cAIDS Division, Ministry of Public Health, Thailand and the dDaniels College of Business, University of Denver, Denver, Colorado, USA.

Correspondence to Usa Thisyakorn, MD, Thai Red Cross AIDS Research Centre, 1871 Rama IV Road, Prathumwan, Bangkok, Thailand 10330. Tel: +66 2 256 4107 9; Fax: +66 2 254 7577; E-mail:

Received: 9 November 1999;

revised: 29 June 2000; accepted: 22 August 2000.

Sponsorship: This study received grant support from the Save the Child's Life Charity Project, Thai Red Cross Society.

© 2000 Lippincott Williams & Wilkins, Inc.