National Geographic Style Manual has moved to
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:
HIV/AIDS 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.