Pediatric Annals

PEDIATRIC IMMUNIZATION UPDATE 

Routine Childhood Vaccination Update: Educating the Office Staff

Sharon G Humiston, MD, MPH, FAAP; Raymond A Strikas, MD

Abstract

Routine universal childhood vaccination has been important for half a century, but it has now become confusing. To simplify matters for the entire office staff, in this article we explain the timing of vaccination and provide an update on specific routine childhood vaccines.

Because a wise person once said, "What you can't keep in your mind you should keep on your wall," we have also included many figures and tables that can be posted as memory aids where vaccines are stored. For example, the "Summary of Rules for Childhood Immunization" (Fig. 1) was created by the Immunization Action Coalition to help office personnel remember everything from the proper route of administration to the true contraindications for each vaccine. The Coalition offers an up-to-date immunization record (Fig. 2) that can be downloaded from their web site (www.immunize.org).

We have not included other important issues (eg, storage and handling, contraindications, or adverse reactions) or other important vaccines (eg, influenza and meningococcal vaccines). Other articles in this issue can be used to develop teaching materials for these topics. Casebased teaching materials on Haemophilus influenzae type b (Hib), hepatitis B, measles, pertussis, influenza, and general childhood immunization are available from the Association of Teachers of Preventive Medicine at 1-800-789-6737.

GENERAL PRINCIPLES

Live Versus Inactivated Vaccines

Currently available vaccines are either live or inactivated. Among the routine childhood vaccines currently used in the United States, only measles-mumps-rubella (MMR) and varicella are live. Unlike inactivated vaccines, these live injected vaccines replicate in the body and usually induce immunity after a single dose. Also, unlike inactivated vaccines, live injected vaccines may be made ineffective by circulating antibodies, including persistent maternal antibodies in infants. For this reason, infants should be scheduled to receive MMR and varicella vaccines on or after their first birthday, when maternal antibodies are unlikely to be present.

Case 1. Max moved to our practice when he was 24 months old. While entering his immunization record onto our form, the astute nurse noted that his first birthday was April 21, but that the MMR vaccine had been given March 21, when he was only 11 months old. What should a health care provider do in this situation? (See the Case Notes at the end of the article.)

Infants born to mothers who were not tested for hepatitis B surface antigen should receive an initial dose of hepatitis B vaccine wimin 12 hours of birth. The mother should be tested immediately, and if results are positive, the infant should receive hepatitis B immune globulin within 7 days. The AAFs Red Book or the ACIP guidelines should be consulted for dose volumes and additional details about this critical preventive intervention. The Immunization Action Coalition's web site (www.immunize.org/ genr.d/ quesfreq.htm) is another source of information.

Case 5. A 3-kg newborn, with a hepatitis B surface antigen-iiegative mother, received a birth dose of hepatitis B vaccine. His second dose was given at the 4-month well-child visit. He was then lost to followup for 8 months. He returned to the practice a week after his first birthday and received another hepatitis B vaccine. How many more doses will he need? (See the Case Notes at the end of the article.)

MMR Vaccine

The MMR vaccine is a combination of three live, attenuated vaccine viruses. Their success is demonstrated by the 100% reductions observed for measles, mumps, and congenital rubella syndrome since vaccines were introduced in the 1960s." The current recommendation is to administer two doses of MMR vaccine subcutaneously - one at 12 to 15 months of age and the second prior to entering elementary school. The purpose of the…

Routine universal childhood vaccination has been important for half a century, but it has now become confusing. To simplify matters for the entire office staff, in this article we explain the timing of vaccination and provide an update on specific routine childhood vaccines.

Because a wise person once said, "What you can't keep in your mind you should keep on your wall," we have also included many figures and tables that can be posted as memory aids where vaccines are stored. For example, the "Summary of Rules for Childhood Immunization" (Fig. 1) was created by the Immunization Action Coalition to help office personnel remember everything from the proper route of administration to the true contraindications for each vaccine. The Coalition offers an up-to-date immunization record (Fig. 2) that can be downloaded from their web site (www.immunize.org).

We have not included other important issues (eg, storage and handling, contraindications, or adverse reactions) or other important vaccines (eg, influenza and meningococcal vaccines). Other articles in this issue can be used to develop teaching materials for these topics. Casebased teaching materials on Haemophilus influenzae type b (Hib), hepatitis B, measles, pertussis, influenza, and general childhood immunization are available from the Association of Teachers of Preventive Medicine at 1-800-789-6737.

GENERAL PRINCIPLES

Live Versus Inactivated Vaccines

Currently available vaccines are either live or inactivated. Among the routine childhood vaccines currently used in the United States, only measles-mumps-rubella (MMR) and varicella are live. Unlike inactivated vaccines, these live injected vaccines replicate in the body and usually induce immunity after a single dose. Also, unlike inactivated vaccines, live injected vaccines may be made ineffective by circulating antibodies, including persistent maternal antibodies in infants. For this reason, infants should be scheduled to receive MMR and varicella vaccines on or after their first birthday, when maternal antibodies are unlikely to be present.

Case 1. Max moved to our practice when he was 24 months old. While entering his immunization record onto our form, the astute nurse noted that his first birthday was April 21, but that the MMR vaccine had been given March 21, when he was only 11 months old. What should a health care provider do in this situation? (See the Case Notes at the end of the article.)

Figure 1. Summary of njles for childhood immunization. Reprinted with permission from the Immunization Action Coalition.

Figure 1. Summary of njles for childhood immunization. Reprinted with permission from the Immunization Action Coalition.

Figure 1. Summary of njles for childhood immunization. Reprinted with permission from the Immunization Action Coalition.

Figure 1. Summary of njles for childhood immunization. Reprinted with permission from the Immunization Action Coalition.

Figure 2. Sampie vaccine administration record for children and adolescents. Reprinted with pennission from the immunization Action Coalition.

Figure 2. Sampie vaccine administration record for children and adolescents. Reprinted with pennission from the immunization Action Coalition.

The Routine Schedule

Figure 3 shows the 2001 recommended harmonized immunization schedule with footnotes. In 1995, the routine vaccination schedule was harmonized by the American Academy of Pediatrics (AAP), the American Academy of Family Physicians (AAFP), and the Advisory Committee on Immunization Practices (ACIP). The harmonized schedule is updated once a year. A copy of the current harmonized schedule is available from the web sites of the Centers for Disease Control and Prevention (CDC) (www.cdc.gov/nip), the AAP (www.aap.org /family/ parents /immunize.htm#pdf), and the AAFP (www.aafp.org/exam/rep-520.html). This also can be posted in the office.

Intervals Between Different Vaccines Not Administered Simultaneously

The number of combination vaccines is likely to increase in the future, which will reduce the number of injections. While we await these combinations, all vaccines for which a child is eligible should be offered simultaneously. This strategy can keep a child on schedule and prevent an additional, unnecessary office visit - a benefit to busy parents. It is safe and effective to use all vaccines simultaneously, provided that vaccines are not combined within a single syringe. There are no contraindications to giving any two different routine childhood vaccines at the same visit.

Vaccines that are not administered at the same visit may be given at any future visit without regard to intervals, with one exception. Live injected vaccines (eg, MMR and varicella) that are not administered simultaneously should be separated by at least 4 weeks. This "4-week separation rule" is intended to reduce the potential risk of interference from the first vaccine on the later vaccine. For example, if varicella vaccine is given 1 week after MMR vaccine, the varicella vaccination should be repeated (or serologic testing could be used to confirm seroconversion).

Minimum Age and Intervals Between Doses In a Vaccine Series

Prolonged intervals between doses in a vaccine series do not diminish vaccine effectiveness. If a boy who received his first hepatitis B vaccine at birth were then lost to follow-up, he could receive a valid second dose of hepatitis B vaccine when seen for his preschool physical examination. This would leave only one dose to administer. The boy could have been protected sooner if his physician's office had had an effective recall system, but at least the hepatitis B vaccine series would not have to be started again from the beginning.

The routine childhood vaccine series never needs to be restarted due to prolonged intervals. In contrast, vaccine doses that are given too early in life or repeated too soon after a previous dose may be ineffective. Table 1 shows such current minimum age and minimal interval recommendations.

Case 2. Occasionally, families do not keep appointments and office staff get confused about when to reschedule appointments. For example, the interval between doses 2 and 3 of the diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine varied for several children. For Quinn it was 2 weeks, for Jocie it was 6 weeks, and for Patrick it was 26 weeks. For which child or children should dose 3 of the DTaP be repeated? (See the Case Notes at the end of the article.)

Intervals Between Uve Vaccines and Blood Products That Contain Antibody

Circulating antibodies against measles, mumps, rubella, or varicella compromise the corresponding live injected vaccine. This is because live vaccine viruses have to replicate in the body to induce immunity and antibody to a virus can prevent this replication. Exceptions are the live oral vaccines such as the no-longer used oral poliovirus and rotavirus vaccines. These replicate in the gut and, therefore, are not affected by circulating antibodies. Inactivated vaccines are not affected greatly by circulating antibodies and can be administered without regard to the relative timing of the administration of products that contain immune globulin.

MMR and varicella vaccines have sufficient time to replicate and induce effective immunity if given 14 days or more before products that contain antibodies. When live injected vaccines are given after blood products that contain antibodies, the situation is more complex. The specific product that contains antibodies and its dose dictate the necessary waiting period before a dose of a live injected vaccine will be valid. Table 2 shows the specific waiting periods after various blood products that contain antibodies.

Figure 3. Recommended childhood immunization schedule-United States, January-December 2001, Reprinted with permission from the Centers for Disease Control and Prevention.

Figure 3. Recommended childhood immunization schedule-United States, January-December 2001, Reprinted with permission from the Centers for Disease Control and Prevention.

Figure 3. Recommended childhood immunization schedule-United States, January-December 2001, Reprinted with permission from the Centers for Disease Control and Prevention.

Figure 3. Recommended childhood immunization schedule-United States, January-December 2001, Reprinted with permission from the Centers for Disease Control and Prevention.

Table

TABLE 1Minimum Age for Initial Vaccination and Minimum Interval Between Vaccine Doses, by Type of Vaccine*

TABLE 1

Minimum Age for Initial Vaccination and Minimum Interval Between Vaccine Doses, by Type of Vaccine*

VACCINE-SPECIFIC UPDATES

Pneumococcal Conjugate Vaccine

Streptococcus pneumoniae (pneumococcus) is one of the remaining major causes of serious infectious childhood diseases, and the emergence of antimicrobial resistance has greatly increased concern about this organism. The pure polysaccharide pneumococcal vaccine (PPV23) prevents invasive pneumococcal disease, but not in those younger than 2 years, the age group with the highest incidence of invasive pneumococcal disease. The new 7-valent pneumococcal conjugate vaccine (PCV7) for infants and young children is analogous to the Hib conjugate vaccine in the sense that a protein has been joined to a capsular polysaccharide. PCV7 contains the 7 serotypes of pneumococcus that account for most of the invasive pneumococcal disease in children younger than 5 years. Pre-licensure studies indicated a high efficacy against invasive disease, a meaningful reduction in acute otitis media disease, and reductions in nasopharyngeal carriage of the bacteria.1

PCV7 is recommmded for all children younger than 24 months and those 24 to 59 months who are at increased risk for pneumococcal disease because of sickle cell disease, functional or anatomic asplenia, human immunodeficiency virus (HIV) infection, immune compromise for any reason, or certain chronic diseases. PCV7 should be considered for all children 24 to 59 months of age, especially those at risk because of age (24 to 35 months old), descent (Alaska Native, American Indian, or African American), or attendance at group day care.

PCW is recommended at 2, 4, and 6 months of age (minimum interval between each dose is 4 weeks) with a single booster dose at 12 to 15 months of age (minimum interval from the primary series to the booster is 8 weeks). Children who start receiving the vaccine after 6 months of age need fewer doses, as shown in Table 3. The article by Baiter and Van Beneden in this issue has more details.

Table

TABLE 2Suggested Intervals Between Administration of Immune Globulin Preparations for Various Indications and Vaccines Containing Uve Measles Virus*

TABLE 2

Suggested Intervals Between Administration of Immune Globulin Preparations for Various Indications and Vaccines Containing Uve Measles Virus*

Case 3. A 23-month-old girl with several episodes of viral-induced wheezing and a strong family history of asthma was seen for well-child care. Is PCV7 recommended for her? (See the Case Notes at the end of the article.)

Hib Vaccine

The near elimination of invasive Hib disease in the United States is a success story of the past 15 years. The Hib vaccines currently in use consist of a capsular polysaccharide bonded to a protein carrier to enhance immunogenicity (especially in infants). Protein carriers include diphtheria toxoid (PRP-D; for use only for children between 15 and 59 months of age, in contrast to the others), a Neisseria meningitidis outer membrane protein complex (PRP-OMP), a mutant diphtheria toxin (HbOC), and tetanus toxoid (PRP-T).

Table

TABLE 3Catch-up Doses of Conjugate Vaccines

TABLE 3

Catch-up Doses of Conjugate Vaccines

The routine Hib vaccine schedule includes doses at 2, 4, and 6 months (the third primary dose is not required in an all PRP-OMP series). A booster is given at 12 to 15 months of age. It is acceptable practice to complete the series with an Hib product different from the one used to start the series. Although an all-PRP-OMP series requires only a 2-dose primary series, any mixed schedule requires a 3-dose primary series. Table 3 indicates the number of doses needed by children who fall behind on their Hib series.

Case 4. A 5-year-old boy came in for school immunizations. There were 12 weeks left before kindergarten started. His entire immunization record had been lost. How many Hib vaccines should he receive before he attends school? (See the Case Notes at the end of the article.)

DTaP Vaccine

DTaP is the recommended form of the oldest combination vaccine, DTP, which has prevented millions of cases of diphtheria, tetanus, and pertussis. DTaP is licensed for all of the preschool doses, starting as early as 6 weeks of age. Unfortunately, although pertussis is not uncommon in older children and adults, no pertussis vaccine is yet licensed for children older than 7 years. Children older than 7 years in need of tetanus toxoid should receive Td (tetanus and diphtheria toxoids, adult type), which contains a lower dose of diphtheria toxoid to rninimize adverse reactions.

Acellular pertussis vaccine replaced whole cell pertussis vaccine as the recommended immunizing agent against whooping cough because, although it is essentially as immunogenic, it is followed by fewer adverse side effects than the whole cell vaccine. Because the licensed acellular pertussis vaccines contain different components, the pertussis vaccination series should be completed with vaccine from the same manufacturer if possible. However, when this is not feasible for any reason, the series can be finished with the DTaP vaccine that is available. Similarly, DTaP can and should be used to complete an immunization series started with DTP.

Table

TABLE 4Recommended Dosages and Schedules of Hepatitis A Vaccines

TABLE 4

Recommended Dosages and Schedules of Hepatitis A Vaccines

Polio Vaccine

In the United States, approximately 21,000 cases of paralytic polio were reported from 1953 to 1954.2 In sharp contrast, since 1979 the only remaining cause of polio in the United States has been vaccineassociated paralytic polio.3 With the change to an allinactivated poliovirus vaccine (IPV) schedule, it is expected that vaccine-associated paralytic polio will also eventually disappear and it is hoped that all polio will be eradicated from the world in our lifetime.

EPV consists of poliovirus killed by formaldehyde. A complete series includes three primary doses and one booster. The minimum interval between each dose is 4 weeks. If an all-LPV schedule is used and the third dose is administered after the child's fourth birthday, no booster dose is indicated.

Hepatitis A Vaccine

Similar to polio, hepatitis A virus is spread in stool and causes more serious disease in adults than in children. Approximately 100 Americans die each year of hepatitis A.4 The vaccine against this virus is now recommended for all children who are 2 years or older and live in areas where the incidence is highest (eg, the western United States).4 Two doses are needed to complete the series and mese should be given at least 6 months apart. Table 4 lists die proper doses for the two brands of hepatitis A vaccine.

Hepatitis B Vaccine

Vaccination with hepatitis B vaccine prevents this infection and its complications, which include cirrhosis of the liver and cancer. The strategy of targeting hepatitis B vaccination toward high-risk individuals failed to control the disease, so in 1991 this strategy was replaced with universal infant vaccination.5 This was augmented by the recommendation for universal adolescent vaccination in 1996.6 Children and adolescents who have not yet been vaccinated should be vaccinated at the earliest opportunity. This can be accomplished in sites other than the medical home (eg, a teen center, a sexually transmitted disease clinic, a school clinic, a family planning clinic, or a juvenile correction clinic). The Vaccines for Children program makes vaccine available for free to those who are eligible until their 19th birthday.

Two recombinant hepatitis B vaccines are licensed for use in the United States, as shown in Table 5. A three-dose vaccination series started with the product of one manufacturer can be completed with that of the other. A two-dose series has been approved for Merck's hepatitis B vaccine (Recombivax, Merck & Co., Inc., West Point, PA): adolescents 11 to 15 years of age usually seroconvert after two doses of Recombivax separated by at least 6 months. Mixing brands for the two-dose hepatitis B schedule is considered "off label use."

The minimum intervals between doses are 4 weeks between doses 1 and 2, 8 weeks between doses 2 and 3, and 4 months between doses 1 and 3. Physicians often find the provisos for the third dose confusing. The third dose should be given at least 8 weeks after the second dose, at least 4 months after the first dose, and no earlier man 6 months of age.

All pregnant women should be screened for hepatitis B surface antigen, and the results of the test should be known by the time of delivery. Perinatal transmission can be prevented by the administration of both hepatitis B vaccine and hepatitis B immune globulin within 12 hours of birth.

Table

TABLE 5Recommended Dosages of Hepatitis B Vaccines'

TABLE 5

Recommended Dosages of Hepatitis B Vaccines'

Infants born to mothers who were not tested for hepatitis B surface antigen should receive an initial dose of hepatitis B vaccine wimin 12 hours of birth. The mother should be tested immediately, and if results are positive, the infant should receive hepatitis B immune globulin within 7 days. The AAFs Red Book or the ACIP guidelines should be consulted for dose volumes and additional details about this critical preventive intervention. The Immunization Action Coalition's web site (www.immunize.org/ genr.d/ quesfreq.htm) is another source of information.

Case 5. A 3-kg newborn, with a hepatitis B surface antigen-iiegative mother, received a birth dose of hepatitis B vaccine. His second dose was given at the 4-month well-child visit. He was then lost to followup for 8 months. He returned to the practice a week after his first birthday and received another hepatitis B vaccine. How many more doses will he need? (See the Case Notes at the end of the article.)

MMR Vaccine

The MMR vaccine is a combination of three live, attenuated vaccine viruses. Their success is demonstrated by the 100% reductions observed for measles, mumps, and congenital rubella syndrome since vaccines were introduced in the 1960s." The current recommendation is to administer two doses of MMR vaccine subcutaneously - one at 12 to 15 months of age and the second prior to entering elementary school. The purpose of the second dose is to immunize children who failed to respond to the initial dose of MMR vaccine. The recommendation to give a second dose was made in 1989 because of the persistence of epidemics of measles among highly vaccinated school children.8

Scientists have not found evidence for a causal relationship between MMR vaccine and autism.

Varicella Vaccine

Varicella vaccine protects against chickenpox and its complications, which were responsible for approximately 11,000 hospitalizations and approximately 100 deaths each year in the United States before 1995.9 The Oka strain - a live, attenuated varicella vaccine virus - was developed in the early 1970s in Japan and is used in the only varicella vaccine licensed in the United States. The seroconversion rate after one dose of vaccine is 97% for children 12 months to 12 years of age; similar seroconversion rates are achieved after two doses in adolescents and adults.10 The efficacy of the vaccine is approximately 70% to 90% for any varicella disease and greater than 95% for severe varicella disease. The breakthrough infection rate is approximately 1% per year for children. Parents should be told of the possibility of breakthrough infection, and that breakthrough illness is generally mild if it occurs. Varicella vaccination reduces the incidence of shingles in the postvaccination years and it may reduce the lifetime incidence of shingles.

Vaccination against varicella is recommended for all healthy children who do not have a reliable history of varicella disease. For children 12 months to 13 years old, a single dose is recommended. For children 13 years or older, two doses separated by 4 to 8 weeks are recommended.11 The article by Watson in this issue contains more information.

CONCLUSION

Childhood infectious diseases that are dismissed as historical may again become acutely relevant if immunization is abandoned as a routine of pediatric practice. If all goes well, and we continue our vaccination efforts, our knowledge of these diseases will be gained through lectures and slide shows only, not through visits to emergency departments and intensive care units.

REFERENCES

1. Centers for Disease Control and Prevention. Preventing pneumococcal disease among iniants and young children: recommendations of the Advisory Committee on Immunization Practices. MMWR. 2000;49(RR09):l-38.

2. Ploktin SA, Orenstein WA, eds. Vaccines, 3rd ed. Philadelphia: W B. Saunders; 1999.

3. Centers for Disease Control and Prevention. Poliomyelitis prevention in the United States: updated recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. 2000;49(RR05):l-22.

4. Centers for Disease Control and Prevention. Prevention of hepatitis A through active or passive immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. 1999;48(RR12):l-37.

5. Centers for Disease Control and Prevention. Hepatitis B virus: a comprehensive strategy for eliminating transmission in the United States through universal childhood vaccination: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. 1991;40(RR13):1-19.

6. Centers for Disease Control and Prevention. Immunization of adolescents: recommendations of the Advisory Committee on Immunization Practices, the American Academy of Pediatrics, the American Academy of Family Physicians, and the American Medical Association. MMWR. 1996; 45(RR13):1-16.

7. Centers for Disease Control and Prevention. Achievements in public health, 1900-1999: impact of vaccines universally recommended for children- United States, 1990-1998. MMWR. 1999;48(RR12):243-248.

8. Centers for Disease Control and Prevention. Measles prevention: recommendations of the Advisory Committee on Immunization Practices (ACIP). AlMWR. 1989;38(SU09):1-18.

9. Centers for Disease Control and Prevention. Prevention of varicella: updated recommendations of the Advisory Committee on Immunization Practices (ACTP). MMWR. 1999;48(RR06):1-5.

10. Lieberman JM. Varicella vaccine: what have we learned? Contemporary Pediatrics. 2001.

11. Centers for Disease Control and Prevention. Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices (ACTP). MMWR. 1996;45(RRll):l-25.

BIBLIOGRAPHY

Atkinson W, Wolfe S, Humiston S, Nelson R. Epidemiology and Prevention of Vaccine-Preventable Diseases, 6th ed. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention; 2001. Available at: www.cdc.gov/nip/publications.

Centers for Disease Control and Prevention. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. Available at: www.cdc.gov/nip/ publications/ ACLP-listhtm.

Immunization Action Coalition. Needle Tips. St. Paul, MN: Immunization Action Coalition. Available at: www. immunize.org.

National Network for Immunization Information. Communicating With Patients About Immunization: A Resource Kit From the National Network for Immunization Information. Available at: www.immunizationinfo.org.

Peter G, ed. 2000 Red Book: Report of the Committee on Infectious Diseases, 25th ed. Elk Grove Village, TL: American Academy of Pediatrics; 2000.

TABLE 1

Minimum Age for Initial Vaccination and Minimum Interval Between Vaccine Doses, by Type of Vaccine*

TABLE 2

Suggested Intervals Between Administration of Immune Globulin Preparations for Various Indications and Vaccines Containing Uve Measles Virus*

TABLE 3

Catch-up Doses of Conjugate Vaccines

TABLE 4

Recommended Dosages and Schedules of Hepatitis A Vaccines

TABLE 5

Recommended Dosages of Hepatitis B Vaccines'

10.3928/0090-4481-20010601-07

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