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Hannah, the spunky central character in the edgy new HBO series “Girls,” is a creative and endearingly naïve 24-year-old bumbling fearlessly through postcollege life. She works for years at an unpaid internship that never turns into a job and pretends to be far more sophisticated about sex than she actually is. She’s a loyal friend, but whatever you do, don’t ask her about human papillomavirus, or HPV. She’s clueless.

The much-discussed third episode of the series, which aired in late April, was rife with misinformation about HPV, a reflection of the real confusion felt by twentysomethings — or perhaps just by the show’s writer, Lena Dunham, who plays Hannah.

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First, our hapless heroine is tested for HPV, an infection linked to cervical cancer, though what she really had been worried about was H.I.V. This is not entirely implausible; still, the test has not been approved for women under age 30. Medical guidelines strongly discourage its use in young women, as the results generally are not meaningful unless a Pap smear also detects signs of abnormal cells.

Hannah can’t believe that the result is positive. Her doctor apparently hasn’t told her that nearly half of women her age have the virus. Usually, it goes away on its own.

Then Hannah is hysterical: She must have her “cervix scraped out.” Actually, it’s the screening test that requires cervical scraping. There is no treatment for an HPV infection.

Hannah accuses her loser boyfriend of infecting her; he swears he tested negative just last week. Here, viewers who were planning to demand their boyfriends get tested, too, are in for a disappointment. There is no HPV test for men, as Hannah’s old college boyfriend notes later in the episode.

Hannah tells her best friend she has “precancer,” though she does not. Precancerous changes would be detectable with a Pap smear, not an HPV test. Her friend, in tears, says, “What if you can’t have children?” Cervical cancer can lead to hysterectomy, and precancerous lesions can complicate pregnancies — but not a passing HPV infection.

It’s hard to know whether blithe ignorance is supposed to be part of Hannah’s charm, or whether the show’s creators just don’t care much for the facts. An HBO spokeswoman said only, “We respect your feedback on ‘Girls’ but must remind you that it is a comedy series and one which we hope people won’t go to for medical advice.”

If only it were so simple. Viewers easily absorb health messages that are embedded in a narrative, research shows. Inaccurate information offered in a story format is recalled more readily than the real facts received during sex education classes or from a doctor, said Al Gunther, a journalism professor at the University of Wisconsin in Madison.

“Storytelling around the fire was our earliest form of communication,” Dr. Gunther said. “Information relayed in that kind of context is more vivid, so it’s much easier to ‘get’ and much easier to remember.” All the more so when viewers identify with a character like Hannah, he added.

In the show’s defense, HPV is a confusing and complicated subject. In women, some strains of the virus cause genital warts, and some cause cancers of the cervix, vagina and vulva; in both sexes, infection can lead to anal and oral cancers.

These strains are common, however, and problematic only when they persist in the body. About 25 percent of the population is infected with HPV at any point in time, but “25 percent of people don’t get cancer,” said Dr. Alan G. Waxman, a professor of obstetrics and gynecology at University of New Mexico in Albuquerque.

The virus is ubiquitous. Most sexually active people are exposed and infected, often repeatedly. “When we think of sexually transmitted infections, the first question is ‘Who’d I get it from?,’ ” Dr. Waxman said. “But it just isn’t that kind of infection. When a woman tests positive for HPV, we don’t know if she got it last month or 10 years ago.”

Good news for Hannah: Most people gain immunity after exposure, said Debbie Saslow, director of breast and gynecologic cancer at the American Cancer Society.

“If you have HPV, it’s probably not going to mean anything,” she said. “It doesn’t mean you’re going to get cancer. As long as you get your follow-up tests, cervical cancer is the most preventable cancer.” HPV tests are overused, she said.

So what’s a sexually active twentysomething to do?

By all means, ask your doctor to test you for sexually transmitted diseases like H.I.V., chlamydia, syphilis and gonorrhea.

Beginning at age 21, have a Pap smear every three years to detect cellular abnormalities and precancerous conditions, which can be treated. You should get regular Pap smears even if you have had the HPV vaccine, because the vaccine protects againstonly some viral strains. There is generally no need for standalone HPV testing until age 30, although it may be performed if a Pap smear turns up abnormal cells.

Protect yourself. Use condoms to prevent sexually transmitted infections even if you are using other contraceptives. Condoms do provide partial protection against HPV infection, and regular condom use protects against the infection’s progression for reasons that aren’t entirely understood.

Don’t smoke. In addition to all of the other health problems associated with tobacco, smoking increases the chance an HPV infection will become chronic.

Finally, take some advice from HBO itself: Television sitcoms are the last place to look for information about sex.

Don’t listen to Hannah, girls.