|HIV (human immunodeficiency virus) and AIDS (acquired
immunodeficiency syndrome) may be used without first defining the
abbreviations. The terms may also be combined with a slash:
statistics are terrifying in sub-Saharan Africa.
Write: AIDS virus or HIV. (Do not say HIV virus; the V in HIV stands for virus.)
Hyphenate HIV-positive and HIV-negative in all uses:
Her test showed she was HIV-negative.