CLINICAL PHARMACOLOGY
Mechanism Of Action
PNEUMOVAX 23 induces type-specific antibodies that
enhance opsonization, phagocytosis, and killing of pneumococci by leukocytes
and other phagocytic cells. The levels of antibodies that correlate with
protection against pneumococcal disease have not been clearly defined.
Clinical Studies
Effectiveness
The protective efficacy of pneumococcal vaccines
containing six (types 1, 2, 4, 8, 12F, and 25) or twelve (types 1, 2, 3, 4, 6A,
8, 9N, 12F, 25, 7F, 18C, and 46) capsular polysaccharides was investigated in
two controlled studies in South Africa in male novice gold miners ranging in
age from 16 to 58 years, in whom there was a high attack rate for pneumococcal
pneumonia and bacteremia.4 In both studies, participants in the
control groups received either meningococcal polysaccharide serogroup A vaccine
or saline placebo. In both studies, attack rates for vaccine type pneumococcal
pneumonia were observed for the period from 2 weeks through about 1 year after
vaccination. Protective efficacy was 76% and 92%, respectively, for the 6- and
12-valent vaccines, for the capsular types represented.
Three similar studies in South African young adult male
novice gold miners were carried out by Dr. R. Austrian and associates5
using similar pneumococcal vaccines prepared for the National Institute of
Allergy and Infectious Diseases, with pneumococcal vaccines containing a
6-valent formulation (types 1, 3, 4, 7, 8, and 12) or a 13-valent formulation
(types 1, 2, 3, 4, 6, 7, 8, 9, 12, 14, 18, 19, and 25) capsular
polysaccharides. The reduction in pneumococcal pneumonia caused by the capsular
types contained in the vaccines was 79%. Reduction in type-specific
pneumococcal bacteremia was 82%.
A prospective study in France found a pneumococcal
vaccine containing fourteen (types 1, 2, 3, 4, 6A, 7F, 8, 9N, 12F, 14, 18C,
19F, 23F, and 25) capsular polysaccharides to be 77% (95%CI: 51% to 89%)
effective in reducing the incidence of pneumonia among male and female nursing
home residents with a mean age of 74 (standard deviation of 4 years).6
In a study using a pneumococcal vaccine containing eight
(types 1, 3, 6, 7, 14, 18, 19, and 23) capsular polysaccharides, vaccinated
children and young adults aged 2 to 25 years who had sickle cell disease,
congenital asplenia, or undergone a splenectomy experienced significantly less
bacteremic pneumococcal disease than patients who were not vaccinated.7
In the United States, one post-licensure randomized
controlled trial, in the elderly or patients with chronic medical conditions
who received a 14-valent pneumococcal polysaccharide vaccine (types 1, 2, 3, 4,
6A, 8, 9N, 12F, 14, 19F, 23F, 25, 7F, and 18C), did not support the efficacy of
the vaccine for nonbacteremic pneumonia.8
A retrospective cohort analysis study based on the U.S.
Centers for Disease Control and Prevention (CDC) pneumococcal surveillance
system, showed 57% (95%CI: 45% to 66%) overall protective effectiveness against
invasive infections caused by serotypes included in PNEUMOVAX 23 in persons
≥ 6 years of age, 65 to 84% effectiveness among specific patient groups
(e.g., persons with diabetes mellitus, coronary vascular disease, congestive
heart failure, chronic pulmonary disease, and anatomic asplenia) and 75% (95%CI:
57% to 85%) effectiveness in immunocompetent persons aged ≥ 65 years of
age. Vaccine effectiveness could not be confirmed for certain groups of
immunocompromised patients.9
Immunogenicity
The levels of antibodies that correlate with protection against
pneumococcal disease have not been clearly defined.
Antibody responses to most pneumococcal capsular types
are generally low or inconsistent in children less than 2 years of age.
Concomitant Administration With Other Vaccines
In a double-blind, controlled clinical trial, 473 adults,
60 years of age or older, were randomized to receive ZOSTAVAX and PNEUMOVAX 23
concomitantly (N=237), or PNEUMOVAX 23 alone followed 4 weeks later by ZOSTAVAX
alone (N=236). At four weeks postvaccination, the varicella-zoster virus (VZV)
antibody levels following concomitant use were significantly lower than the VZV
antibody levels following nonconcomitant administration (GMTs of 338 vs. 484
gpELISA units/mL, respectively; GMT ratio = 0.70 (95% CI: [0.61, 0.80]).
Limited safety and immunogenicity data from clinical
trials are available on the concurrent administration of PNEUMOVAX 23 and
vaccines other than ZOSTAVAX.
REFERENCES
4. Smit, P.; Oberholzer, D.; Hayden-Smith, S.; Koornhof,
H.J.; Hilleman, M.R.: Protective efficacy of pneumococcal polysaccharide
vaccines, JAMA. 238: 2613-2616, 1977.
5. Austrian, R.; Douglas, R.M.; Schiffman, G.; Coetzee,
A.M.; Koornhof, H.J.; Hayden-Smith, S.; Reid, R.D.W.: Prevention of
pneumococcal pneumonia by vaccination, Trans. Assoc. Am. Physicians. 89: 184-194,
1976.
6. Gaillat, J.; Zmirou, D.; Mallaret, M.R.: Essai clinique
du vaccin antipneuomococcique chez des personnes agees vivant en institution,
Rev. Epidemiol. Sante Publique. 33: 437-44, 1985.
7. Ammann, A.J.; Addiego, J.; Wara, D.W.; Lubin, B.;
Smith, W.B.; Mentzer, W.C.: Polyvalent pneumococcal-polysaccharide immunization
of patients with sickle-cell anemia and patients with splenectomy, N. Engl. J.
Med. 297: 897-900, 1977.
8. Simberkoff, M.S.; Cross, A.P.; Al-Ibrahim, M.:
Efficacy of pneumococcal vaccine in high risk patients: results of a Veterans
Administration cooperative study, N. Engl. J. Med. 315: 1318-27, 1986.
9. Butler, J.C.; Breiman, R.F.; Campbell, J.F.; Lipman,
H.B.; Broome, C.V.; Facklam, R.R.: Pneumococcal polysaccharide vaccine
efficacy. An evaluation of current recommendations, JAMA. 270: 1826-31, 1993.