Table 1. Selected model input parameters in the CEPAC-Pediatric natural history model for internal validation analyses.

Data from the IeDEA East Africa cohort [28]		Value
Monthly risk of clinical events (%) a		Infants <6m of age		Children ≥6m of age
WHO Stage 3 event		5.2-7.8		3.3-11.6
WHO Stage 4 event		1.6-3.5		1.4-6.4
Tuberculosis event		0.5-1.1		0.8-3.8
Risk of death within 30 days of clinical event (%)
After WHO Stage 3 or 4 event		3.4
After TB event		2.8
Monthly risk of death in infants and children with no history of clinical event (%)
CD4% < 15		0.4
CD4% 15-24		0.4
CD4% ≥ 25		0.3
Monthly risk of death in infants and children with history of clinical event (%, occurring >30 days post-event))
CD4% < 15		2.4
CD4% 15-24		0.8
CD4% ≥ 25		0.4
Data from WITS [33]b	Value		Range evaluated in internal validation analyses
Initial CD4% distribution at birth (mean, SD)	42.0% (9.4%)		42.0% - 50.0% c
Monthly rate of CD4% decline	1.4%		0.3% - 8.0% c

IeDEA: International Epidemiologic Databases for the Evaluation of AIDS; WHO: World Health Organization; TB: tuberculosis; WITS: Women and Infants Transmission Study.

a. WHO Stage 4, Stage 4, and TB events defined according to WHO classifications for HIV disease staging in children [3].

b. The publicly available WITS dataset includes 193 perinatally HIV-infected children (positive HIV co-culture or PCR by 4-6 weeks of age), with a median of 5.2 months of follow-up prior to initiation of 3-drug ART (Interquartile Range (IQR): 2.1-12.1 months; AZT monotherapy was permitted during the follow-up period) [33]. Of the 193 perinatally HIV-infected children included in the WITS dataset, 180 (93%) had at least one CD4% measurement before ART initiation, 152 (79%) had at least two values, and 121 (63%) had at least three; the first recorded CD4% was observed at a median age of 5.0 days (IQR: 1.0-29.0 days)

c. See derivation of ranges for sensitivity analyses in Methods.