NEW YORK — Signs of the cancer-causing human papilloma virus in women near or at menopause may be a reawakened dormant infection, suggesting a risk for women who came of age in the ‘‘sexual revolution’’ in the 1960s and ’70s.
About 77 percent of the infections were detected in women who reported five or more sexual partners in their lifetime, according to a study in the Journal of Infectious Diseases. The findings released Thursday suggest that reactivation of the sexually transmitted virus may increase around age 50 and be responsible for more later-life infections than new ones, researchers said.
The data raises a new concern for women now entering menopause, suggesting a significantly higher risk for HPV infections than those of the previous generation, researchers said. The findings may mean that women need to continue routine screening after age 40, said Patti Gravitt, one of the study authors.
HPV is found in about a quarter of teenage girls and about half of women age 20 to 24, according to a 2007 study in the Journal of the American Medical Association. There isn’t a good test for men. Previous studies have found that the virus isn’t detected in samples after about two years.
The immune system may be controlling it, Gravitt said. If the immune system weakens, as it does with age, the virus can come back. HPV is linked to head and neck, cervical, vulvar, vaginal, penile, and anal cancer, and is the most common sexually transmitted disease in the United States.
The first vaccine to prevent HPV infection, Merck & Co.’s Gardasil, was approved in 2006 in the United States and is recommended to prevent cervical cancer in girls and women from 9 to 26 years old. It’s also approved to prevent genital warts and anal cancer in boys and men of the same ages. GlaxoSmithKline’s HPV vaccine Cervarix was approved in 2009 for preventing cervical cancer in females age 9 to 25.
The reactivation of the infection seems similar to that of the varicella zoster virus that causes chickenpox. The virus can lie dormant in the bodies of people who were infected as children, then come raging back as shingles later in life, the authors wrote. That may be what’s happening with these women around menopause, said the study authors.
Though it’s not clear why the infection comes back, scientists suspect it may be because of age-related changes in the immune system.