This is kind of a murky area, with debate between activists and public policy experts. You will be asked to notify, or have the health department notify, anyone you have had sex with or shared needles with since your last negative HIV test or, if you’ve never had one, the most recent sex partners (say, in the last year). Your partner(s) will need to be tested now and, if the test is negative, again in three months (the window period between infection and when it actually shows up on a test). According to the New York Department of Health, how far back in time known partners should be reported is determined on a case-by-case basis depending on such factors as the approximate dates when you believe you were exposed and became infected and how willing (or able) you are to dig up those names and contact info, with the priority on current and recent partners. The federal Ryan White Care Act requires states to make a good-faith effort to notify current spouses and anyone who has been the HIV-positive person’s spouse within the last 10 years. Therefore, spouses within the last 10 years, if known, should be notified, unless you’ve had a negative HIV test result since then. Do know that public health departments and clinics are not supposed to pressure you for this information and they cannot withhold your test results or penalize you in any way for not divulging this info.