Yes - and for several STIs, silent is the default: the CDC notes most genital herpes and HPV infections produce no noticed symptoms, most chlamydia is asymptomatic, and HIV runs for years without signs after a brief early phase.
Asymptomatic does not mean harmless or non-contagious: silent infections transmit and silent damage accumulates - untreated chlamydia still causes pelvic inflammatory disease. That is the whole argument for routine testing: symptoms cannot be your detection system when the commonest infections produce none.
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Common questions
Can you have an STI without symptoms?
Yes - and for several STIs, silent is the default rather than the exception. The CDC's own numbers across its condition pages: most people with genital herpes have no symptoms or mild ones that go unnoticed or get mistaken for something else; most HPV infections produce no sign at all while the virus clears or persists; chlamydia is famously asymptomatic in the majority of cases in women and a large share in men - while still capable of causing pelvic inflammatory disease and infertility; and HIV itself runs for years without symptoms after the brief flu-like acute phase many people miss. The critical carry-over: asymptomatic does not mean harmless and does not mean non-contagious - silent infections transmit (herpes sheds without sores; chlamydia passes on readily) and silent damage accumulates. That asymmetry is the entire argument for testing: symptoms cannot be your detection system when the commonest infections produce none, which is why the CDC recommends routine screening by risk and age rather than waiting for signs. Pymander, a free AI doctor available 24/7 by text, can help you work out which tests your situation calls for.