Factors associated with vertical HIV transmission during two different time periods: the impact of zidovudine use on clinical practice at a Brazilian reference centre

Abstract

Vertical HIV transmission rates and associated factors among mother-infant pairs cared for at a Brazilian reference centre from 1988 to 1993 (period 1), and from 1996 to 1999 (period 2) were evaluated. A total of 150 and 239 infants born to HIV+ mothers were enrolled at birth during these periods. No zidovudine prophylaxis was available in period 1. In period 2, 92.4% of the infants were exposed to zidovudine (54% started at delivery or in the post-natal period). During period 1, 25 of 129 infants were found to be infected (19.4%; 95% confidence interval [CI]=13-27) vs 20 of 232 (8.6%; 95% CI=5-13) during period 2 (P <0.01). After controlling for co-variables, this decline was due to zidovudine prophylaxis, either with complete (odds ratio [OR]=0.24; 95% CI=0.08-0.70) or incomplete (OR=0.37; 95% CI=0.17-0.81) regimens. Premature rupture of membranes (OR =3.2) and rhesus-negative blood type of the infant (OR=2.6) facilitated transmission. Although confirming the protective effect of zidovudine prophylaxis, alternative approaches aimed at pregnant women identified late are needed for this population.

Mother-to-child transmission of HIV in Brazil during the years 2000 and 2001: results of a multi-centric study

“…Evaluation of the two periods, done by the reference service of the city of Riberão Preto (São Paulo State), revealed a reduction of 44.3% in the transmission rate when comparing the periods 1988-1993 and 1996-1999 21 . Meanwhile, in a developed country (the United States), a comparison of the two periods revealed an even greater fall: from 18.1% in the period 1990-1992 to 1.6% in the period 1999-2000 22 .…”

“…The reduction of mother-to-child transmission of HIV when effective antiretroviral therapy is made available has been demonstrated in various studies 7,20,21,23,24 . Antiretroviral use both in treating the mother's condition and preventing mother-to-child transmission, has been increasing in the last decade in all regions of the country, but the use of medication is far from uniform.…”

Twenty-five years of the AIDS epidemic in Brazil: principal epidemiological findings, 1980-2005

“…The incremental increase of female participation, in its turn, resulted in an increase in the number of children infected via vertical transmission, a trend partially reverted by the institution of vertical transmission prophylaxis, beginning with those measures implemented after Protocol ACTG 076 19 . With the progressive country-wide implementation of measures established by Protocol ACTG 076, a substantial reduction in the number of pediatric AIDS cases was observed 20 , principally when the trends were analyzed by year of birth 21 , corresponding, in some studies, to less than 10% of the cases anticipated, for children born from 2001 on 22 . Meanwhile, because of the precariousness of access to prenatal care and its poor quality 23 , characterized by lack of HIV testing in pregnant women and/or poorer counseling, especially among the pooer 24,25 , vertical transmission continues to be a relevant problem in some parts of the country 26,27 .…”

Mother-to-child transmission of HIV: risk factors and missed opportunities for prevention among pregnant women attending health services in Goiânia, Goiás State, Brazil

“…After the implementation of the prevention measures by the Brazilian Ministry of Health, the rates of vertical transmission have varied between 2.5% and 8.6% in Brazil 17,18,19,20,21,22,23 . These estimates were obtained predominantly from reference centers in the Southeastern Region, and do not necessarily reflect the existing conditions in the majority of healthcare services.…”