Table 1.

Descriptions of the States Used in Models

Abbreviation	State	Definition
PS	Presymptomatic SCID	No overt signs of illness; the only medical encounters are for routine baby care.
O	Outpatient	Two or more trips/month to either doctor’s office or emergency department because of illness related to SCID—infections, graft versus host diseases (GVHD), diarrhea, fail to thrive (FTT).
I	Inpatient	Hospitalization for one or more nights per month for a medical condition related to SCID infections.
H	HCT	A one-month period including preparation and administration of bone marrow.
PH	Post-HCT	Inpatient SCID patient remains in the hospital. Hospitalization might be required for T cell lymphopenia, isolation, infection, GVHD, etc.
		Outpatient SCID patient is out of the hospital, but still needs one or more medical visits/month for tests and interventions.
SW	SCID Well	A post-BMT state in which a SCID patient is thriving but still receiving immunoglobulin to provide antibody protection.
D	Decreased	Death
UW	Unaffected Well	Child unaffected with SCID
UD	Unaffected Death	Death of a child unaffected with SCID