Final answer:
Chlamydia, caused by the bacterium Chlamydia trachomatis, is the most common STD in the US, especially among teens and young adults.
Step-by-step explanation:
The most common STD in the US is chlamydia. Chlamydia is a sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis. It is considered the most common bacterial STI in the United States, particularly affecting teens and young adults. Females are much more likely than males to contract chlamydia. While there are other common STIs like genital herpes, gonorrhea, and the Human Papillomavirus (HPV), chlamydia has higher reported rates.
Gonorrhea, caused by Neisseria gonorrhoeae, is also common and can lead to serious health issues if left untreated. Viral infections such as HPV and herpes simplex virus 2 (HSV-2) can cause persistent sexual transmission risks due to their incurable nature. Despite the prevalence of viral STIs, including the most common viral STI, HPV, chlamydia remains the most commonly reported bacterial STI in the United States.