Exposure type	Infection status of source
	HIV-positive class 1*	HIV-positive class 2*	Source of unknown HIV status†	Unknown source‡	HIV-negative
Less severe§	Recommend basic two-drug PEP.	Recommend expanded three-drug PEP.	Generally, no PEP warranted; however, consider basic two-drug PEP|| for source with HIV risk factors.¶	Generally, no PEP warranted; however, consider two-drug PEP|| in settings where exposure to HIV-infected persons is likely.	No PEP warranted
More severe#	Recommend expanded three-drug PEP.	Recommend expanded three-drug PEP.	Generally, no PEP warranted; however, consider basic two-drug PEP|| for source with HIV risk factors.	Generally, no PEP warranted; however, consider basic two-drug PEP|| in settings where exposure to HIV-infected persons is likely.	No PEP warranted