There is no single federal law that answers whether you legally have to tell someone you have an STD, but roughly two dozen states make it a crime to have sex without disclosing an HIV-positive status, other states can prosecute knowing transmission under general assault or reckless endangerment laws, and every state allows an infected partner to sue you in civil court. Whether disclosure is legally required in your situation depends on the state you’re in, the specific infection, and what you knew at the time.
When Nondisclosure Is a Crime
About 33 states have criminal laws written specifically to address HIV exposure or transmission. Of those, 24 explicitly require people who know they are HIV-positive to disclose that status to sexual partners before any sexual contact.1PubMed Central (PMC). Prevalence and Public Health Implications of State Laws that Criminalize Potential HIV Exposure in the United States Under statutes like these, the crime is the failure to disclose. A charge can stick even if the partner was never actually infected.
States without HIV-specific statutes are not necessarily safer ground. Prosecutors there regularly charge knowing or reckless STD transmission under general laws covering assault, battery, or reckless endangerment. The practical difference: general statutes usually require proof that transmission actually occurred and that the person acted with knowledge or reckless disregard, while HIV-specific laws may criminalize nondisclosure by itself.
Penalties vary widely. A misdemeanor conviction might mean up to a year in jail and a fine. Felony charges, still on the books in some states for HIV-related offenses, can carry multi-year prison sentences. In a small number of states, a conviction under an HIV-specific criminal statute can trigger sex offender registration, even when the underlying sexual contact was consensual.
Which STDs Can Trigger Charges
HIV dominates the statute books, but it is not the only infection that can lead to prosecution. Some states have broad communicable disease statutes that criminalize willful exposure of another person to any infectious disease with significant public health implications. Under laws like these, herpes, syphilis, and other serious or incurable infections can carry criminal penalties if you know you’re infected and expose a partner without disclosure. The elements prosecutors typically need to prove are that you knew about the infection, that you intended to or recklessly did expose someone, and that the conduct created a substantial risk of transmission.
Civil claims are broader still. A person who knowingly transmits any sexually transmitted infection, from chlamydia to hepatitis, can face a lawsuit for damages. Courts do not limit civil cases to a specific list of diseases the way some criminal statutes do.
How Treatment Affects Your Legal Exposure
Medical advances have outpaced the law. The scientific consensus known as “U=U” (undetectable equals untransmittable) holds that a person living with HIV who maintains an undetectable viral load through treatment poses effectively no risk of sexual transmission.2PubMed Central (PMC). Ending Overly Broad Criminalization of Nondisclosure of Human Immunodeficiency Virus Infection That reality has produced pressure to reform criminal laws written in the 1980s and 1990s, when an HIV diagnosis was essentially a death sentence.
Several states have modernized their HIV criminalization statutes. Common reforms include reducing felony charges to misdemeanors, requiring proof of intent to transmit rather than just nondisclosure, and recognizing that steps to prevent transmission (such as maintaining viral suppression or using condoms) should reduce or eliminate criminal liability. This is a fast-moving area, so the rules in your state may have changed recently.
Even in states that have modernized, these defenses typically have to be raised and proven by the defendant. An undetectable viral load does not automatically immunize you from prosecution. You would need medical records showing consistent treatment and suppression around the time of the encounter.
Civil Lawsuits a Partner Can File
Criminal charges require a prosecutor to act. Civil lawsuits don’t. An infected partner can file a personal injury claim directly, and the legal theories are well established in every state.
- Battery. If you knew you were infected and had sexual contact with someone who did not know, courts treat that as harmful or offensive contact regardless of whether the sex itself was consensual. Consent to sex is not the same as consent to infection.
- Negligence. If you knew or should have known about your infection and failed to take reasonable precautions, that is a straightforward negligence claim. “Should have known” can include situations where you had obvious symptoms but avoided getting tested.
- Intentional infliction of emotional distress. Deliberately concealing an STD from a partner and then infecting them can qualify as extreme and outrageous conduct, opening the door to additional damages.
Damages cover medical bills for testing, treatment, and ongoing care, which can reach tens of thousands of dollars over a lifetime for incurable infections. Courts also award compensation for emotional distress, pain and suffering, and lost wages. For intentional conduct, punitive damages may be available on top of compensatory damages.
Causation is the hardest piece. The infected partner must show that you were the source, not someone else. Defense attorneys regularly point to the plaintiff’s other sexual partners or the possibility of prior infection. Medical records, timelines, and sometimes genetic sequencing of the pathogen become critical evidence.
Defenses to a Transmission Claim
Several established defenses may apply if you are facing a claim, and they also shape what a plaintiff has to prove.
- Lack of knowledge. This is the most successful defense in practice. If you genuinely did not know you were infected at the time of the encounter, liability is extremely difficult to establish. Courts apply a reasonableness standard, so willful ignorance (refusing to get tested despite clear symptoms) will not protect you, but a truly asymptomatic infection you had no reason to suspect can.
- Assumption of risk. If you disclosed your infection and your partner understood the risk and voluntarily chose to proceed, that partner has essentially assumed the risk. The disclosure has to be clear, and the partner has to have actually understood what they were agreeing to.
- Contributory negligence. In some jurisdictions, if the infected partner was also negligent, such as refusing to use protection despite knowing the risks, that can reduce or eliminate the defendant’s liability.
One defense does not work: arguing that because the sex was consensual, no liability can attach. Courts consistently distinguish between consenting to sexual activity and consenting to exposure to a disease. Someone who lies about their STD status or conceals it cannot hide behind the partner’s consent to the act itself.
How Long a Partner Has to Sue
If you’ve been infected by a partner who concealed their status, timing matters. The statute of limitations for STD-related civil claims varies by state and by the legal theory. Negligence claims typically have a two-to-three-year window, battery claims run two to four years, and fraud-based claims can extend to six years in some states.
The critical detail is when the clock starts. Most states apply a “discovery rule,” meaning the limitations period begins when you discover (or reasonably should have discovered) that you were infected, not when the sexual contact occurred. For infections with long latency periods, like HIV or HPV, this distinction can add years to your filing window.
Situations That Change the Picture
Immigration
Certain STDs can affect eligibility for a U.S. visa or permanent residency. Under federal immigration law, an applicant determined to have a “communicable disease of public health significance” is inadmissible.3Office of the Law Revision Counsel. 8 US Code 1182 – Inadmissible Aliens The CDC defines that list by regulation, and it currently includes gonorrhea and infectious-stage syphilis. HIV was removed from this list in 2010.4U.S. Department of State. Ineligibility Based on Health and Medical Grounds – INA 212(a)(1) An applicant diagnosed with a listed disease during the required immigration medical exam faces denial unless the condition is treated before adjudication.
Military Service
Service members face a separate and often stricter framework. Under the Uniform Code of Military Justice, HIV-positive service members who have unprotected sex without disclosing their status have been convicted of aggravated assault with a means likely to cause death or grievous bodily harm. Courts-martial have also sustained charges for transmitting herpes under similar theories. Beyond criminal prosecution, STD-related misconduct can result in nonjudicial punishment, administrative reprimand, or separation from service. Military personnel are typically ordered to follow specific safe-sex directives after an HIV diagnosis, and violating those orders is itself a chargeable offense.
Removing a Condom Without Consent
A growing number of states have passed laws specifically addressing “stealthing,” the act of removing a condom during sex without a partner’s consent. These laws are directly relevant to STD transmission because condom removal eliminates a key barrier to infection. A few states now treat stealthing as a form of sexual battery under civil law, allowing victims to sue for damages. The legal landscape is evolving quickly, and more states are expected to follow.
If You’ve Been Exposed
If you believe a partner concealed an STD from you, the steps you take in the first days and weeks matter for both your health and any eventual legal claim. Get tested immediately and keep all medical records, including the date of your diagnosis and the specific pathogen identified. Document your communications with the partner, especially any messages where they denied having an infection or acknowledged concealing one. If you know the approximate date of exposure and the date of diagnosis, that timeline becomes central to proving your case.
Comprehensive STI screening panels at private labs typically cost between $50 and $400, depending on which infections are tested. Filing a civil lawsuit involves initial court fees that generally fall in the $200 to $500 range, with attorney costs on top of that. Many personal injury attorneys handle STD transmission cases on a contingency basis, meaning you pay nothing upfront and the attorney takes a percentage of any recovery. Whether you pursue a civil claim, a criminal complaint, or both, early documentation is the single most important thing you can do to preserve your options.