to delivery, 20 percent during delivery, and 39 percent postpartum during breast feeding (Kourtis et al., 2006). Various antepartum, intrapartum, and postpartum regimens with AZT have all been shown to reduce transmission of HIV from mother to infant (Connor et al., 1994; Guay et al., 1999; Lallemant et al., 2000; Petra Study Team, 2002; Shaffer et al., 1999). The administration of an abbreviated antepartum course of zidovudine to the mother (for 4 to 6 weeks) is effective, but is less so than longer courses (Lallemant et al., 2000). When a shorter antepartum course is used, the addition of lamivudine to the mother’s regimen has been shown to increase its effectiveness (Chaisilwattana et al., 2002; Dabis et al., 2005; Mandelbrot et al., 2001). Adding single-dose nevirapine to short-course AZT for the mother may also improve efficacy in breast-fed and formula-fed infants (Dabis et al., 2005; Shapiro et al., 2006), and when the mother does not receive treatment, single dose nevirapine plus AZT for the infant has better efficacy than nevirapine alone (Taha et al., 2003, 2004). Either administering antiretrovirals to a breast-feeding infant or treating the infant’s HIV-infected mother can also greatly reduce transmission during breast feeding (Chasela et al., 2010; Kumwenda et al., 2008).
WHO Recommendations to Prevent MTCT of HIV
In 2010 WHO revised its 2006 guidelines for PMTCT and the care of mothers and recommended initiation of ART for all HIV-infected pregnant women with CD4 counts below 350/mm3 (from below 200/mm3 in 2006) or in WHO clinical stage 3 or 4 (WHO, 2006, 2010a). The 2010 WHO PMTCT guidelines recommended that all infants born to women receiving ART should receive either AZT or nevirapine for 4 to 6 weeks and that those mothers who do not need ART for their own health should start ARV prophylaxis as early as 14 weeks of pregnancy, replacing the initiation at 28 weeks in the 2006 recommendations. The 2010 guidelines also recommended two options for PMTCT, Option A and Option B.24 The guidelines placed the responsibility on national authorities to decide whether mothers
24 Option A includes zidovudine (AZT) antepartum, with nevirapine/AZT/lamivudine (3TC) during labor and delivery. AZT/3TC should then be continued for 7 days postpartum. The infant, if breast fed, should receive nevirapine for a minimum of 4 to 6 weeks from birth until 1 week after exposure to breast milk has stopped. Non-breast feeding infants should all receive either daily infant nevirapine or single dose nevirapine with AZT for 4 to 6 weeks.
Option B includes AZT/3TC/lopinavir/ritonavir or the substitution of abacavir or efavirenz for lopinavir/ritonavir starting from 14 weeks gestation until delivery or until 1 week after exposure to breast milk has stopped if breast feeding. Alternatively tenofovir disoproxil fumarate/3TC or emtricitabine/efavirenz could be used. In Option B, all infants should receive nevirapine or AZT for 4 to 6 weeks.
In both Option A and B, women should be treated according to existing WHO guidelines for treatment initiation (WHO, 2010a).