Published: May 3, 2007
Updated: Oct. 1, 2007
An Update on Pediatrics Vaccines
In my office I see an increasing number of parents who ask about new vaccines for their children that they’ve heard about.
For adolescent girls there is a new vaccine to prevent cancer, and for infants there is a vaccine to decrease the disease caused by rotavirus.
Both of these infections claim a lot of parental time or cause personal anxiety -- or both. Joseph St. Geme, MD, chair of Duke’s Department of Pediatrics, provides details about these two new vaccines in this month’s bulletin.
-- Dennis Clements MD, PhD, MPH
Vaccines are among the greatest advances in medicine -- they have had a dramatic effect in limiting disease and death in children who have received recommended vaccinations.
Investigators continue to develop new vaccines, aiming to prevent infections that remain commonplace. In the past 18 months, two newly developed vaccines have been added to the recommended schedule of routine vaccines in children and adolescents, namely rotavirus vaccine (RotaTeq®) and human papilloma virus (HPV) vaccine (Gardasil®).
Rotavirus is an intestinal virus that is the most common cause of gastroenteritis (intestinal infection) in children and infects virtually all children by the age of three years. Rotavirus gastroenteritis typically includes fever, vomiting, and diarrhea, and often lasts a week or longer.
Most rotavirus infections are mild, but severe dehydration develops in approximately one in 50 patients. Each year rotavirus infection results in hospitalization of 50,000 infants younger than two years of age in the United States and leads to an estimated 480,000 to 640,000 deaths in developing countries.
In 2006 a new vaccine against rotavirus called RotaTeq was licensed by the Food and Drug Administration for use in the United States. The beneficial effects of RotaTeq have been assessed in two large clinical trials of almost 70,000 children that examined a three-dose series.
In one of these trials, the full series was 74 percent effective against rotavirus gastroenteritis of any kind and 98 percent effective against severe rotavirus gastroenteritis.
In the other study, the full series reduced the incidence of rotavirus-related office visits by 86 percent, emergency room visits by 94 percent, and hospitalizations by 96 percent.
An earlier rotavirus vaccine called RotaShield® was licensed in 1998 but was withdrawn from the market roughly one year later after reports of an increased incidence of a form of intestinal obstruction called intussusception. The studies of RotaTeq® have not revealed any increase in risk of intussusception.
According to current Centers for Disease Control recommendations, all full-term infants should receive RotaTeq. There is limited information on immunization of infants born at less than 37 weeks gestation, but consideration should be given for immunization of these children because they may be at increased risk for hospitalization from gastroenteritis in the first year of life.
The schedule for immunization with RotaTeq is as follows:
The primary side effects associated with RotaTeq® are mild, short-lived diarrhea or vomiting, which develop in approximately 1 to 3 percent of children within seven days of receiving a dose of the vaccine.
Human papillomaviruses (HPV) are a group of more than 120 different viruses. Approximately 40 HPV types are primarily sexually transmitted from person to person infecting the oral, anal, or genital areas of both men and women.
By the age of 50 years, 70 to 80 percent of men and women have acquired genital HPV infection. Most genital HPV infections cause no symptoms and are cleared by the immune system within a few weeks or months without any consequence.
However, some people develop persistent genital HPV infection, with potential to result in cancer or genital warts.
HPV types 16 and 18 are considered high-risk types and may cause abnormal Pap smears and cervical cancer in women. Collectively types 16 and 18 account for approximately 70 percent of the cases of cervical cancer in the United States.
Infection with high-risk HPV types is also believed to cause 85 percent of anal cancers, 50 percent of other anogenital cancers, 20 percent of cancers of the throat and mouth, and 10 percent of cancers of the larynx and esophagus.
HPV types 6 and 11 are responsible for more than 90 percent of genital warts. These types can spread from mother to infant during pregnancy or delivery and rarely result in warts in the throat or larynx of the child.
In 2006 an HPV vaccine called Gardasil® was licensed by the Food and Drug Administration for use in the United States. Gardasil® contains fragments of HPV types 6, 11, 16, and 18 and has been studied in over 11,000 females between 9 and 26 years old in many countries, including the United States.
Among women and girls who had not been exposed to HPV types 6, 11, 16, and 18, the vaccine was 100 percent effective in preventing cervical pre-cancers caused by the targeted HPV types and was nearly 100 percent effective in preventing vulvar and vaginal pre-cancers and genital warts caused by the targeted HPV types.
According to current recommendations, vaccination against HPV is recommended for all girls 11 to 12 years of age and can be initiated in girls as young as nine years of age. Catch-up vaccination is recommended for females 13 to 26 years of age who have not been vaccinated previously or who have not completed the full vaccine series, whether or not they have had sexual intercourse or previous evidence of HPV infection.
If a girl or woman is already infected with one of the HPV types in the vaccine, the vaccine will not prevent disease from that type.
The schedule for vaccination with Gardasil® consists of three doses. The second dose is administered two months after the first dose, and the third dose is administered four months after the second dose.
The side effects of the Gardasil® vaccine have been limited to pain, swelling, and redness at the injection sites in some recipients.
-- Joseph St. Geme, MD, is chair of Duke’s Department of Pediatrics.
-- Dennis Clements, MD, PhD, is the chief of primary care pediatrics atDuke Children's Hospital.