Backgrounder

Adolescent Immunization Backgrounder
The US immunization program vaccination schedule is a blueprint that provides people with a continuum of immunity throughout their lives. While our immunization program produces high vaccination rates in infants and toddlers, data from the Centers for Disease Control and Prevention (CDC) show that recommended vaccines are underused in adolescents. This is due to a variety of factors including few regular wellness visits, and parents and providers treating immunization as lower priority for pre-teens and teens. It is critical to focus on vaccinating adolescents to ensure disease prevention and to encourage a lifelong commitment to better preventive healthcare through immunization. 

Recommended Vaccinations 
There are many vaccines recommended for adolescents. Three are recommended for first-time administration at 11-12 years of age. They are the meningococcal conjugate (MCV4); tetanus, diphtheria, and pertussis (Tdap) booster; and human papillomavirus (HPV). The influenza vaccine is recommended annually for all adolescents. “Catch-up” vaccines, for adolescents who were not immunized or were underimmunized as infants and toddlers, are hepatitis B; polio; measles, mumps, and rubella (MMR); and varicella (chickenpox). Finally, two vaccines are recommended for adolescents with certain risk factors: hepatitis A and pneumococcal

The CDC, American Academy of Pediatrics, American Academy of Family Physicians, American Medical Association, and Society for Adolescent Health and Medicine all recommend a routine healthcare visit that includes vaccination at 11-12 years of age. Adolescents who are not vaccinated at this age should have their vaccines brought up-to-date as soon as possible.

Serious and Deadly Diseases that Vaccines Can Protect Against 

Meningococcal disease
There are approximately 1,000 cases of meningococcal disease in the US each year. Anyone can get meningococcal disease, but adolescents have an increased risk of getting the disease. Even with rapid, appropriate treatment, approximately 10-14 percent of people who become infected will die and 15 percent of survivors will suffer complications including brain damage, hearing loss, and amputations. 

The most common clinical presentations of meningococcal disease are meningitis and meningococcal bacteremia; each can occur alone or in combination with the other. Meningococcal disease is marked by frequently nonspecific symptoms at onset and very rapid progression that can kill an otherwise healthy adolescent in less than 48 hours. 

The meningococcal conjugate vaccines (MCV4) are effective and safe in protecting against four of the five meningococcal serogroups (A, C, Y, and W-135) that cause most disease in adolescents and adults. Currently, no licensed US vaccine protects against serogroup B. 

Vaccination is recommended for all adolescents at 11-12 years of age, with a booster dose at age 16. For those who receive the first dose at 13-15 years of age, a booster is recommended at 16 through 18. Adolescents should receive one meningococcal vaccine dose less than five years before starting college. Adolescents with no spleen or HIV need two doses two months apart from the first time they are immunized (i.e., at 11-12 years of age).

Human papillomavirus virus
HPV has been associated with cervical cancer and anogenital cancers such as cancer of the vulva, vagina, penis, and anus. Some studies also support a role of genital types of HPV in non-genital cancers including oral cavity and pharyngeal cancers. 

HPV vaccination is recommended for routine administration in females and males at 11-12 years of age through a three-dose series over six months. It is recommended for all females through age 26 years and males through age 21 years, who did not get any or all of the recommended vaccine doses when they were younger. The vaccine is also recommended for all males who have sex with males and males with compromised immune systems (including HIV) through age 26 years, if they were not fully vaccinated when they were younger. The vaccine is safe for all males through age 26 years.

There are two vaccines available to prevent HPV infection: the quadrivalent vaccine and the bivalent vaccine. Both vaccines can be given to females; the quadrivalent vaccine can only be given to males. Both protect against strains 16 and 18; these strains are responsible for about 70 percent of cervical cancers. One of the vaccines also protects against strains 6 and 11, which are associated with 90 percent of genital warts. HPV infection can also be prevented by abstaining from sexual contact. Neither vaccine eliminates the need for cervical cancer screening, because the vaccines do not protect against all HPV infections that cause cervical cancer.

Pertussis, tetanus, and diphtheria  
Pertussis is the least well-controlled vaccine-preventable bacterial disease in the US. Although most infants and toddlers are vaccinated against pertussis, immunity wanes after about 5 to 10 years, so adolescents can get whooping cough. The illness is usually milder in them (they may never know they had it), but adolescents are common transmitters of the infection to infants, who are at the highest risk of death. In fact, a whooping cough outbreak that occurred in California in 2010 was responsible for the death of 10 infants. In recent years, the US has experienced the highest number of pertussis cases since 1959. In 2012, outbreaks were reported in a majority of states with more than 32,000 cases and 16 deaths, most of which were in infants. This is why a booster vaccination at 11-12 years of age is important, and also why pregnant women need to get Tdap vaccination in the second or third trimester. Tdap protects pregnant women, their developing babies, and eventually their newborns.

Diphtheria is rare in the US, however, it still exists in other countries and can pose a serious threat to any individual not fully immunized who travels abroad or who has contact with infected foreigners in the US. 

The bacteria that cause tetanus are everywhere, living in dirt and soil all around us, but cases are rare because of widespread immunization. Tetanus occurs in about 20 to 30 people in the US each year, resulting in approximately three deaths annually. 

The tetanus, diphtheria, and pertussis booster replaces the previously recommended tetanus and diphtheria (Td) booster at 11-12 years of age or in older adolescents who need a Td booster. The vaccine is also recommended in place of one Td booster for adults who have not previously received Tdap. The CDC advisory committee recommends pregnant women in their second or third trimester vaccinate for whooping cough to potentially pass on antibodies to the fetus, thereby protecting mother and child.

Influenza 
Influenza and its complications are responsible for 3,000-49,000 US deaths each year, depending on the severity of the circulating viruses. The CDC recommends annual influenza vaccination for everyone age 6 months and older. 

While influenza is generally more severe in the very young and older persons, adolescents, even healthy ones, can suffer extreme consequences and even death (though rare). School-age children also have the highest influenza attack rates.

Hepatitis B
The majority of new hepatitis B infections in the US occur in young adults. Widespread infant immunization, however, has led to dramatic overall decreases in US incidence from an average of 260,000 in the 1980s to about 38,000 in 2008. An estimated 1.25 million Americans have chronic hepatitis B infection. Chronic infection can lead to cirrhosis, liver cancer, and death. Each year about 3,000 to 5,000 people die from cirrhosis or liver cancer caused by HBV. 

Since routine vaccination of US children and adolescents younger than 19 years of age who have not been vaccinated at birth began in 1991, the reported incidence of acute hepatitis B among children and adolescents has dropped by more than 95 percent. Catch-up vaccination of adolescents would decrease the incidence of hepatitis B in the US even further.

Polio
In the early 1950s, more than 20,000 cases of polio occurred each year. After routine vaccination began in 1955, the number of cases dropped to about 3,000 by 1960; by 1979, there were only about 10 cases annually. While no polio has been reported in the US for over 20 years, the virus continues to circulate globally and importation and outbreaks are a possibility if high vaccination rates are not maintained. 

Measles, mumps, and rubella (MMR)
In the past, approximately 450,000 individuals in the US got the measles and 450 died from it each year. Since the development and use of the vaccine, measles cases have been reduced by 99 percent in the US. However, a measles outbreak occurred in Minnesota during March 2011. An unvaccinated infant who got the disease after traveling outside the country spread the highly contagious infection to at least 21 other individuals resulting in 14 children being hospitalized. As of July 2011, 156 measles cases were reported nationally, with a hospitalization rate of 50 percent. That represents more cases than reported annually since 1996. 

Widespread transmission of rubella (German measles) has been eliminated and the US has experienced greater than a 92 percent decline in mumps cases and greater than a 99 percent decline in mumps deaths due to vaccination. 

Varicella
The risk of complications from varicella (chickenpox) varies with age. Among children 1 to 14 years of age, the fatality rate from varicella is approximately 1 per 100,000 cases. Among young people 15 to 19 years, it is 2.7 per 100,000 cases. Catch-up vaccination during adolescence will continue to provide protection against varicella during adulthood.

Hepatitis A
High rates of hepatitis A occur in children and adolescents age 5 to 14 years who live in parts of the US where the disease is more prevalent and most cases occur because of person-to-person transmission.  Vaccination is recommended for children and adolescents in regions where infection rates were more than twice the national average (20 or more cases per 100,000) during the baseline period of 1987-1997. These states are Alaska, Arizona, California, Idaho, Nevada, New Mexico, Oklahoma, Oregon, South Dakota, Utah, and Washington.

Since 1996, and particularly since ACIP's 1999 recommendations for routine vaccination of children living in areas with consistently elevated hepatitis A rates, national hepatitis A rates have declined sharply.

Pneumococcal disease
Although the incidence of pneumococcal disease among adolescents is the lowest of any age group, about 6.8 million children and adolescents age 2 to 18 years have chronic illnesses―such as diabetes or heart, lung, liver, or kidney disorders―that place them at high risk for pneumococcal disease and its complications. For these reasons it is important to have this population vaccinated.

Selected References
CDC. Vaccination Information Statements. Available at: http://cdc.gov/vaccines/pubs/vis/default.htm.  Accessed December 10, 2012.

CDC. Recommendations of the Advisory Committee on Immunization Practices. MMWR. Available at: http://www.cdc.gov/vaccines/recs/acip/default.htm. Accessed December 10, 2012.

CDC. Epidemiology and Prevention of Vaccine-Preventable Diseases. Atkinson W, Wolfe S, Hamborsky J, McIntyre L, eds. 12th ed. Washington DC: Public Health Foundation, 2011. Available at: http://www.cdc.gov/vaccines/pubs/pinkbook/default.htm. Accessed December 10, 2012.

CDC. Prevention of Hepatitis A Through Active or Passive Immunization. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5507a1.htm. Accessed December 10, 2012.

Roush SW, Murphy TV, Vaccine-Preventable Disease Table Working Group. Historical Comparisons of Morbidity and Mortality for Vaccine-Preventable Diseases in the United States. JAMA. 2007;298(18):2155-2163. 

Wasley A, Samandari T, Bell BP, Incidence of Hepatitis A in the United States in the Era of Vaccination. JAMA. 2005;294:194-201. 

Dagan R, Klugman KP. Impact of conjugate pneumococcal vaccines on antibiotic resistance. Lancet Infect Dis. 2008;8(12):785-795.