US health authorities on Friday urged all boys age 11-12 to get a routine vaccination against the most common sexually transmitted disease, human papillomavirus, or HPV.
Other changes as part of an annual update to US immunization schedules included a recommended hepatitis B vaccine to the protect the livers of adults up to age 60 who have diabetes and a vaccine against whooping cough for pregnant women.
The updates, agreed upon by the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP), were published in the CDC's Morbidity and Mortality Weekly report of February 3.
The HPV vaccine has been approved for girls since 2006 but the CDC had not expressly urged it for boys, though boys were included among those who could receive it to prevent certain cancers and genital warts.
Health experts have expressed hope that if pre-teen boys and girls are both encouraged to get the vaccine, the rate of infection will decrease in the general population.
About half of all sexually active adults will get HPV in their lifetime. There are more than 100 types of HPV, and most clear the body on their own, but some strains can linger and lead to cervical, anal or oral cancer.
Only about 20 percent of women aged 19-27 reported having received the HPV vaccine in 2010, up slightly from 17.6 percent in 2009, the CDC said.
The vaccine, currently recommended for girls age 11-26, has faced resistance from some parents over fears that immunizing young girls would encourage them to be promiscuous.
The new guidelines, which were first urged by ACIP in October, call for all males aged 11-12 to get the vaccine too, with a catch up vaccination for those between the ages of 13 and 21 if they missed it.
HPV vaccine also is recommended for males 22-26 years old who have not been vaccinated before and who have weakened immune defenses, who test positive for human immunodeficiency virus (HIV), or who have sex with men.
The hepatitis B shot is now being recommended for all adults up to 60 who have diabetes as soon as possible after they are diagnosed, and for those older based on the need for assisted blood glucose monitoring.
The combination Tdap vaccine against tetanus, diphtheria, and acellular pertussis (or whooping cough) had been urged for adults with close contact to children and for women after they gave birth if they had not previously been vaccinated as adults.
The new recommendation calls for pregnant women to get the Tdap vaccine at 20 weeks gestation or later so they can pass the antibodies on to the fetus.
All people age six months and older can get the annual flu vaccine, the update added. Patients with an egg allergy should get the inactivated flu shot.