Table 2.

Incidence density rates of hypersensitivity reactions within 42 days of abacavir initiation, by screening period

Adjudicated hypersensitivity reaction definition	Screening period	Hypersensitivity reaction events	Person-days on abacavir	Incidence rate per 100,000 person-days (95% CI)	Post- vs. pre-screening incidence rate ratio (95% CI)
Any hypersensitivity reactiona	Pre-screeningb	51	129,856	39 (30, 52)	1.00 (Ref)
	Post-screeningc	37	232,905	16 (12, 22)	0.36 (0.23, 0.55)
Definitive/probable hypersensitivity reactiond	Pre-screeningb	42	129,856	32 (23, 44)	1.00 (Ref)
	Post-screeningc	27	232,905	12 (8, 17)	0.31 (0.19, 0.52)

^aDefined as definite, probable or possible hypersensitivity reaction diagnoses

^bPre-screening period: 01 January 1999 to 14 June 2008

^cPost-screening period: 15 June 2008 to 31 July 2016

^dDefined as definite or probable hypersensitivity reaction diagnoses only