. Author manuscript; available in PMC: 2011 May 3.

Published in final edited form as: J Acquir Immune Defic Syndr. 2010 Jul 1;54(3):311–316. doi: 10.1097/QAI.0b013e3181d61c2e

TABLE 1.

Population Attributable Fractions (PAFs) for Maternal CD4+ Counts (CD4s) (cel ls/mm³), Maternal Plasma Viral Loads (VLs) (copies/mL), and Combined Maternal CD4s-V Ls.

Risk Factor	Late Postnatal Period^*	Total Incidences (I)^†	Expected Incidences (I₀)^‡	PAF ^§	95% CI
VL > 50 000	42-182 Days	48	37.3	22.0%
	183-365 Days	30	12.3	59.0%
	42-365 Days	78	49.5	37.0%	22.0%, 51.0%
CD4+ < 200	42-182 Days	51	34.8	32.0%
	183-365 Days	26	22.4	14.0%
	42-365 Days	77	57.2	26.0%	12.0%, 36.0%
CD4+ < 200 and VL > 50 000	42-182 Days	48	41.0	15.0%
	183-365 Days	25	20.2	19.0%
	42-365 Days	73	61.1	16.0%	6.0%, 25.0%

CI, Confidence Interval

Number of days after birth

^†

six infants of LPT with unknown maternal plasma viral loads and seven infants of LPT with unknown maternal CD4+ counts

^‡

Model-based estimates of expected number of incidences in reference group

^§

PAF = (1-I₀/I)×100%