To the Editor:
There were some comments about pneumococcal conjugate vaccine in the article by Drs. Baiter and Van Beneden in the June issue of Pediatric Annals.1 They recommended reimmunizing with the 7-valent pneumococcal conjugate vaccine (PCV7) in children older than 2 years who have already been immurtized with the 23-valent polysaccharide vaccine (PPV23). I do not understand the rationale for this repeat momunization with a vaccine that has no additional serotypes in a patient who is already adequately immunized. I am unaware of any studies that have shown that this is valuable, and it certainly is costly.
Michael J. Holland, MD
Minot, North Dakota
1. Baiter S, Van Beneden C. An update on the new pneumococcal conjugate vaccine. Pediatr Ann. 2001;30: 350-353.
The authors' response:
We appreciate Dr. Holland's request for the rationale behind vaccinating children from 2 to 5 years old with the newly licensed 7-valent pneumococcal conjugate vaccine (PCV7) following prior vaccination with the 23-valent polysaccharide vaccine (PPV23). This recommendation, which is not universal but specific to children at high risk of pneumococcal infection (eg, children with sickle cell disease, human immunodeficiency virus [HIV] infection, other immunocompromising conditions, or chronic cardiac or pulmonary disease), was issued by both the Advisory Committee on Immunization Practices (ACIP) and the American Academy of Pediatrics (AAP).1'2
The children for whom the ACIP and the AAP recommend PCV7 following PPV23 are those who have the highest rates of disease among this age group, many times greater than the rates among healthy children of the same age.1,2 Although PPV23 has been shown to have some efficacy against invasive pneumococcal disease in adults, it has not been shown to protect against noninvasive pneumococcal infections, there are no direct efficacy data in pediatric populations at increased risk for disease, and reports of vaccine failure in children with sickle cell disease are common.3"5 Also, the response to some common pediatric serotypes is decreased among children 2 to 5 years old.6
In contrast, advantages of conjugate vaccines over polysaccharide vaccines include the induction of immune memory, which will likely result in a longer duration of protection; reduction in carriage of vaccinetype pneumococcal serotypes; and greater efficacy against noninvasive manifestations of infection, such as otitis media and nonbacteremic pneumonia.1'711 Also, although unproven by efficacy studies, the probable benefits of the conjugate vaccine in preventing invasive pneumococcal infections among children 2 to 5 years old who are at high risk are indicated by the results of immunogenicity studies among certain high-risk groups (ie, sickle cell disease or HTV) and results from evaluations of healthy older children that suggest superior response compared with vaccination with PPV23 alone.1213
The AQP and the AAP recommended the use of both PCV7 and PPV23 based on the known and theoretical advantages of PCV7 in the context of a frequent and potentially severe health threat among children at high risk of pneumococcal disease.1,2
Chris Van Beneden, MD, MPH
Respiratory Diseases Branch
National Center for Infectious Disease
Sharon Baiter, MD
Epidemiology and Surveillance Division
National Immunization Program
Centers for Disease Control and Prevention
1. Centers for Disease Control and Prevention. Preventing pneumococcal disease among infants and young children: recommendations of the Advisory Committee on Immunization Practices. MMWR. 2000;49(RR-9):l-38.
2. American Academy of Pediatrics, Committee on Infectious Diseases. Policy statement: recommendations for the prevention of pneumococcal infections, including the use of pneumococcal conjugate vaccine (Prevnar), pneumococcal polysaccharide vaccine, and antibiotic prophylaxis. Pediatrics. 2000;106:362-366.
3. Wong WY, Overturf G, Powars DR. Infection caused by Streptococcus pneumoniae in children with sickle cell disease: epidemiology, immunologic mechanisms, prophylaxis, and vaccination. Clin Infect Dis. 1992;14:1124-1136.
4. John AB, Ramlal A, Jackson H, Maude GH, Sharma AW, Serjeant GR. Prevention of pneumococcal infection in children with homozygous sickle cell disease. Br Med J. 1984;288:1567-1570.
5. Fiore AE, Butler JC, Levine OS, Elliott JA, Facklam RR. Effectiveness of pneumococcal polysaccharide vaccine for preschool-age children with chronic disease. Emerg Infect Dis. 1999;5:828-831.
6. Douglas RM, Paton JC, Duncan SJ, Hansman DJ. Antibody response to pneumococcal vaccination in children younger than five years of age. J Infect Dis. 1983;148:131-137.
7. Black S, Shinefield H, Ray P, et al. Efficacy of heptavalent conjugate pneumococcal vaccine (Wyeth Lederle) in 37,000 infants and children: impact on pneumonia, otitis media and an update on invasive disease: results of the Northern California Kaiser Permanente Efficacy Trial. Presented at the 39th Interscience Conference on Antimicrobial Agents and Chemotherapy; September 26-29, 1999; San Francisco, CA.
8. Black S, Shinefield H, Fireman B, et al. Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Pediatr Infect Dis J. 2000;19:187-195.
9. Obaro SK, Huo Z, Banya WA, et al. A glycoprotein pneumococcal conjugate vaccine primes for antibody responses to a pneumococcal polysaccharide vaccine in Gambian children. Pediatr Infect Dis J. 1997;16:11351140.
10. O'Brien KL, Steinhoff MC, Edwards K, Keyserling HL, Thorns ML, Madore DV. Immunologic priming of young children by pneumococcal glycoprotein conjugate, but not polysaccharide, vaccines. Pediatr Infect Dis J. 1996;15:425-430.
11. Mbelle N, Huebner RE, Wasas AD, Kimura A, Chang I, Klugman KP. Immunogenicity and impact on nasopharyngeal carriage of a nonvalent pneumococcal conjugate vaccine. } Infect Dis. 1999;180:1171-1176.
12. Vernacchio L, Neufeld EJ, MacDonald K, et al. Combined schedule of 7-valent pneumococcal conjugate vaccine followed by 23-valent pneumococcal vaccine in children and young adults with sickle cell disease. JPediatr. 1998;133:275-278.
13. King JC Jr, Vink PE, Farley JJ, et al. Comparison of the safety and immunogenicity of a pneumococcal conjugate with a licensed polysaccharide vaccine in human immunodeficiency virus and non-human immunodeficiency virus-infected children. Pediatr Infect Dis J. 1996;15: 192-196.