Time flies -- and there are few things that dramatize that fact as vividly for a pediatric physician as learning that a patient you've cared for practically all her life is getting ready to go off to college. I've known Molly since she was a sprightly three-year-old. Now she's a high school senior who will be heading to a university in the Boston area next fall.

When Molly's mom brought her by for a checkup recently, she asked my advice about protecting her daughter against two serious conditions that can affect teenagers -- both of which have received some frightening media attention over the past few years. One is meningococcal infection, which can strike suddenly and is sometimes fatal even in previously healthy teens. The other is a concern specifically for young women: HPV, or human papilloma virus, which can lead to cervical cancer.

For this edition of "Your Child's Health," I asked my colleague Samuel Katz, MD, a specialist in pediatric infectious diseases and chairman emeritus of Duke's Department of Pediatrics, to share his thoughts on teen vaccines. He weighed in not only on the concerns raised by Molly's mother, but on other immunizations that may be helpful for older children and adolescents, especially those who may have missed earlier shots or require additional protection.

--Dennis Clements, MD, PhD

Dr. Katz

Parents most often think of immunizations for their children in the first 18 months of life and again when they enter school at age five or six. However, a new paradigm is emerging with a focus on teenagers or preteens. Three new vaccines have become available to help protect adolescent health. All have been endorsed by the American Academy of Pediatrics, the American Academy of Family Physicians, and the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention.

The first, licensed earlier in 2005, is a newer, more effective product to prevent meningococcal infection. The three principal groups of organisms responsible for meningitis and severe bloodstream infections in this country are the meningococcus, the pneumococcus, and haemophilus influenza B. Very successful vaccines for the latter two have already been in use for several years; as a result, there has been a striking decrease in those infections. The only vaccine available for the meningococcus, however, has had only limited efficacy.

Two major age groups are most at risk for a meningococcal infection: infants and young children in the first several years of life, and teenagers -- particularly those who reside in college dormitories. Both Duke and the University of North Carolina have had instances of meningococcal infections among students. Ten percent of such infections may result in death, while others may cause devastating permanent effects such as mental retardation, loss of limbs, and skin scarring.

The vaccine is recommended at age 11 or 12, or at high school entry, as well as to entering college freshmen, especially those who will be living in dormitories, travelers to endemic countries, and any other high-risk groups. For those youngsters who receive meningococcal vaccine at age 11 or 12, a booster is recommended five years later as protection wanes. This is especially important for those who go on to college and live in dormitories.

The second of the new vaccines are designed to protect women against the human papillomaviruses (HPV), which are sexually transmitted. Why give this vaccine to teenagers? At least two types of HPV are responsible for more than 75 percent of cervical cancers, which are second only to breast cancer as the most frequent malignancy among women. The viruses cause precancerous changes in the cells lining the cervix of the uterus (which regular Pap tests are recommended to detect).

Studies show that the new HPV vaccines effectively prevent this persistent infection and, therefore, can be expected to dramatically reduce the incidence of cervical cancer. Because HPV transmission begins with the onset of sexual activity, it is logical that the vaccine be administered to young girls before they become sexually active. 

In October 2011, HPV vaccine (the Gardasil product containing types 6, 11, 16, and 18) has been recommended also for young males, beginning at age 11-12 years. This is based on the increasing recognition that several of the serotypes in the vaccine protect against genital warts, and a number of significant male cancers -- penile, anal, and oropharyngeal. This is especially important for males who have sex with males.

A third infection for which we have immunized infants and children for many years is pertussis -- also known as whooping cough. It has recently become apparent that the current vaccines, which have been employed for more than half a century, protect only for five to 10 years. Most children receive their last injection prior to entering school so that 10 years later, as adolescents, they need a booster.

A special vaccine known as Tdap has been formulated to boost protection against diphtheria and tetanus as well as pertussis. Pertussis in adolescents or adults does not always feature the disease's characteristic "whoops" -- it may appear as only a chronic cough lasting more than two weeks and sometimes for several months. Such a booster not only protects the individual teenagers, but also avoids transmitting the bacterium to infants (siblings or those encountered outside the home) too young to have been fully vaccinated. These infants often become severely ill and may even die.

Although hepatitis B vaccination is recommended for infants shortly after birth and throughout the first six months of life, many youngsters reach school without ever having had their hepatitis immunization. Therefore, another aspect of teenage immunization may be a hepatitis “catch-up” at age 11-13 years if a youngster has not previously received a full course of hepatitis B vaccine. Similarly, some children may never have had their second dose of measles-mumps-rubella (MMR) vaccine; that, too, could be administered at an adolescent visit.

The American Academy of Pediatrics has encouraged families to have their children seen at around age 12 for health assessment and management of any problems. Such a visit is a perfect time at which to check on the need for these newer vaccines or for additional doses of the “old” ones. Many children see physicians or other health care workers for examinations prior to participation in sports, camping events, travel, applying to college, and so on. These visits provide a perfect opportunity to assess the need for any or all of the new vaccines and to initiate them at that time. The meningococcal vaccine and the pertussis vaccine require only a single injection. The papillomavirus vaccine, however, requires three, making it necessary to schedule additional visits beyond the initial one.

However these vaccines and schedules work out, the goal is to protect young people against serious, preventable diseases, to assist them in achieving maximum health benefits, and to prevent their spreading infection to others.

Samuel Katz, MD, is the Wilburt Cornell Davison Professor and chairman emeritus of pediatrics at Duke University Medical Center.

Dennis Clements, MD, PhD, is the chief of primary care pediatrics at Duke Children's Hospital.