Summary of transmission probabilities by antiretroviral regimen and maternal CD4 count
| Peripartum transmission | Postnatal transmission per month of any BF* (except incident infection) | |||||
|---|---|---|---|---|---|---|
| Regimen | CD4 count not specified | CD4<200 | CD4 200–350 | CD4 350+ | CD4<350 | CD4>350 |
| Incident infections (range of reported transmission probabilities) | 30% (13%–30%)6–9 | 28% (14.3%–56%)10–15 | ||||
| No prophylaxis (range of reported transmission probabilities) | 22% (15%–25%)16–20 | 37% (22%–54%)18 21 22 | 27% (13.1%–32.6%)18 21 | 15% (9.7%–20.2%)18 21 22 | 1.57%/m BF23–25 | 0.51%/m BF 23–25 29 30 |
| sdNVP (range of reported transmission probabilities) | 12% (9.4%–12.1%)31–34 | 1.57%/m BF23–25 | 0.51%/m BF23–25 29 30 | |||
| WHO 2006 dual prophylaxis (range of reported transmission probabilities) | 4% (2.3%–5.3%)29 30 35–37 | 1.57%/m BF23–25 | 0.51%/m BF23–25 29 30 | |||
| Option A‡ | 4%† As WHO 2006 | 2%24 29 36 | 0.2%/m BF39 40 | |||
| Option B§ | 2% (0.9%–2.9%)24 41–44 | 0.2%/m BF24 39 43–45 | ||||
| ART (range of reported transmission probabilities) | 2%24 29 30 41–43 | 0.2%/m BF29 30 43–45 | ||||
| ART (before pregnancy) | 0.5%24 42 46 47 48 | 0.16%/m BF24 39 43 44 | ||||
Shading indicates transmission probabilities that are not estimated for a particular regimen either because the regimen is not recommended for women with a particular CD4 count, for example, Option A or B for women with CD4 counts less than 350 cells/ml, or because transmission data were not available for a regimen by CD4 count, for example, sdNVP in women with CD4 350–500 cells/ml.
*For the transmission probabilities associated with breast feeding the values are given to two decimal places since rounding these values up or down would result in significantly greater or lesser transmission rates when multiplied according to the duration of breast feeding.
†Providing Option A to breastfeeding mothers with CD4 counts 200–350 is not recommended. However, it is noted that this situation may arise in settings where systems to perform CD4 counts are not in place and women needing to be on lifelong ART are not being readily identified.
‡In Option A, HIV-positive pregnant women who are eligible for lifelong ART should be started on treatment in the first trimester of pregnancy. HIV-positive pregnant women who are not eligible for ART should receive daily AZT from 14 weeks gestation until delivery, single dose nevirapine during labour and AZT+3TC during labour and for 7 days post partum. HIV-exposed infants would receive AZT or NVP until 6 weeks of age and if breast feeding then NVP would continue until 1 week after all breast feeding has stopped.
§In Option B, HIV-positive pregnant women who are eligible for lifelong ART should be started on treatment in the first trimester of pregnancy. HIV-positive pregnant women who are not eligible for lifelong ART should receive one of four combinations of ARVs during pregnancy throughout the breastfeeding period and 1 week after. Exposed infants would receive either AZT or NVP for 1 week.
3TC, lamivudine; ART, antiretroviral therapy; ARV, antiretroviral drug; AZT, zidovudine; BF, breastfeeding; sdNVP, single dose nevirapine.