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DISEASES CAUSED BY STREPTOCOCCUS PNEUMONIAE . Non-invasive diseaseSinusitis (sinuses)Otitis media (middle ear)Pneumonia (lungs). Musher, in Principles and Practice of Infectious Diseases, 1995. Invasive diseaseBacteraemia (blood) Meningitis (CNS)Endocarditis (heart)Peritonitis (body cavity)Septic arthritis (bones and joints)Others (appendicitis, salpingitis, soft-tissue infections).
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1. PNEUMOCOCCAL DISEASE: A MAJOR HEALTH THREAT Pneumococcal disease: caused by Streptococcus pneumoniae
Pneumococcal disease: a major threat to health
Non-invasive diseases (e.g. otitis media, pneumonia)
Invasive diseases (e.g. bacteraemia, meningitis)
Invasive pneumococcal disease is serious and has a high risk of mortality
Groups at high risk include elderly persons, persons with chronic diseases, asplenic patients, immunocompromised patients
2. DISEASES CAUSED BY STREPTOCOCCUS PNEUMONIAE
3. PNEUMOCOCCUS: TRANSMISSION AND COLONISATION
4. PNEUMOCOCCUS: PATHOGENESIS
5. PNEUMOCOCCAL EPIDEMIOLOGY: AT-RISK GROUPS (1) ELDERLY PERSONS
Laboratory reports of bacteraemic pneumococcal infection per 100 000 population, by age group, in England and Wales
6. THE OVERLAP BETWEEN PNEUMOCOCCAL PNEUMONIA AND INVASIVE PNEUMOCOCCAL DISEASE
7. PNEUMOCOCCAL DISEASE: PNEUMONIA (4) Complications
Bacteraemia in 15-30% of patients with pneumonia1,2
high mortality despite appropriate antibiotic therapy
overall case fatality rate 15-20% for pneumococcal bacteraemia
higher case fatality rates (30-40%) for elderly persons and other vulnerable groups
Spread of pneumococci in the blood to other normally sterile sites can cause other invasive pneumococcal diseases (e.g. meningitis)
Empyema (pus in the pleural cavity) in about 2% of cases3
8. PNEUMOCOCCAL DISEASE: MENINGITIS (1) Meningitis
Inflammation of the meninges (membranes surrounding the brain)
Can be caused by a range of microorganisms, as well as be a manifestation of some non-infectious diseases
Pneumococcal meningitis
Invasive pneumococcal disease
Generally, pneumococci invade the CNS from the blood stream
Signs and symptoms1
Early stages: fever, irritability, neck stiffness, drowsiness
Later stages: headache, seizures, coma
The signs and symptoms are not specific to pneumococcal disease
9. PNEUMOCOCCAL DISEASE: MENINGITIS (2) Pneumococcal meningitisľa high risk of mortality
Case-fatality rate about 30% in adults1
Higher (about 55%) in older patients and other vulnerable groups2
Disability among survivors1
Learning disability
Hearing loss
Blindness
Paralysis
10. INTRODUCTION: PNEUMOCOCCAL DISEASE (2)
11. EPIDEMIOLOGY: INVASIVE PNEUMOCOCCAL DISEASE (3) PNEUMOCOCCAL MENINGITIS1,2
Annual incidence 1-2/100 000 persons
Higher among young children and elderly persons
at least 10 times the incidence among an elderly (ł60 years) population than among younger adults (20-29 years of age)2
Case-fatality rates are high
about 30% in adults and 6% in children3
12. PNEUMOCOCCAL DISEASE: MEDICAL MANAGEMENT (1) Hospitalisation
Often required in high-risk groups and/or in severe forms of pneumococcal disease
Sometimes admission to an intensive care unit is necessary
Empiric treatment using broad-spectrum antimicrobial agents
To cover all possible bacterial aetiological agents
To overcome increasing antimicrobial resistance to antibiotics
High-cost management
13. PNEUMOCOCCAL DISEASE:A SUMMARY S. pneumoniae
A bacterium surrounded by a polysaccharide capsule that protects it from phagocytosis
Many different serotypes
Pneumococcal disease
Invasive pneumococcal disease is serious and has a high risk of mortality
Risk factors include old age, chronic illness, asplenia and immunodeficiency
Mortality remains high despite appropriate antibiotic therapy
S. pneumoniae resistance to antimicrobials is increasing (with concomitant increasing cost of management)
Prevention of pneumococcal disease among high-risk groups is a priority
14. PNEUMOCOCCUS: DIVERSITY OF SEROTYPES There are at least 90 different serotypes of
S. pneumoniae1,2
Each has a capsule of a different chemical composition
Each stimulates the production of a different antibody
Only a minority of serotypes cause most cases of human disease
8-10 cause two-thirds of serious pneumococcal infections in adults3
15. PNEUMOCOCCAL VACCINES: ANTIGEN COMPOSITION 23-valent pneumococcal vaccine contains purified capsular polysaccharides derived from 23 S. pneumoniae serotypes1
1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A,11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F, 33F
Serotype coverage2,3
85-90% of serotypes responsible for all cases of invasive pneumococcal disease
Vaccine includes major serotypes that have developed antimicrobial resistance
Cross protection within some serotypes1
For example, antibody response to serotype 6B protects against serotype 6A, which is not in the vaccine
16. PNEUMOCOCCAL VACCINES: IMMUNE RESPONSE Vaccine stimulates 23 type-specific anti-capsular antibodies1
Antibodies aid the destruction of pneumococci by white blood cells
The immune response in most elderly patients ł 65 years of age:
is as good as that of healthy younger adults1
is variable according to serotypes2
The response is decreased in:
immunosuppressed individuals (e.g. patients with leukaemia, lymphoma, multiple myeloma, or AIDS)3
Antibody levels generally last 5 years or more4
Note: it is inappropriate to use 23-valent vaccine in children under 2 years of age, because the immune response in this age group is poor 3
17. PNEUMOCOCCAL VACCINES: OVERVIEW OF EFFECTIVENESS Case-control and indirect cohort studies on the effectiveness of the pneumococcal vaccine in preventing invasive pneumococcal disease
18. PNEUMOCOCCAL VACCINES: CLINICAL EFFECTIVENESS Estimation of effectiveness of pneumococcal vaccination in preventing invasive pneumococcal disease caused by vaccine serotypes
US Centers for Disease Control study in 2837 patients (ł 5 years old) by underlying illness, 1978-1992
19. PNEUMOCOCCAL DISEASE PREVENTION: VACCINATION RECOMMENDATIONS WHO view (Technical Advisory Group convened by WHO Regional Office for Europe, 1988)1
Pneumococcal vaccination should be recommended for all elderly persons (aged ł60-65 years) and for persons of any age at high risk of acquiring pneumococcal infection
National recommendations
Many countries recommend vaccination for specific at-risk groups or conditions
Some countries recommend vaccination for elderly persons aged:
ł60 years: Belgium, Germany, Iceland
ł65 years: Denmark, Finland, Norway, Sweden, USA, Canada, New Zealand
20. PNEUMOCOCCAL DISEASE PREVENTION: VACCINATION RECOMMENDATIONS Immunocompromised Cardiopulmonary Nursing Age >
Country Asplenia Haematological HIV diabetes, renal Other home 65 years
Austria l - - l ** l - -
Belgium l l l l l l l ***
Denmark l l l l - - l
Finland l l l l l - l
France l l - l ** l - -
Germany l l - l - - -
Iceland l l - l l l l ***
Ireland l l l l l - -
Italy l - l - - - -
Luxembourg l l l l l l l ***
Netherlands l * * * * - -
Norway l l l l l - l
Sweden l l l l l - l
Switzerland l l l l l - -
UK l l l l l - -
USA l l l l l l l
21. PNEUMOCOCCAL DISEASE PREVENTION: OPPORTUNITIES FOR VACCINATION
22. PNEUMOCOCCAL DISEASE PREVENTION: OVERALL VACCINATION RATES Pneumococcal vaccination rates in the USA, Canada and western Europe in 1996
23. PNEUMOCOCCAL DISEASE PREVENTION: PHARMACOECONOMICS The cost-effectiveness of vaccination to prevent pneumococcal bacteraemia in persons aged ł65 years was recently evaluated in the USA
24. PNEUMOCOCCAL DISEASE: CONCLUSIONS Pneumococcal disease
Major cause of morbidity and mortality worldwide
Diagnosis not always made and difficult to establish
Treatment may be complicated by antibiotic resistance
Management can be costly
Prevention by vaccination is a priority in populations who are at risk:
The elderly
Patients with chronic cardiovascular, pulmonary, renal, hepatic and metabolic disorders
Patients who are immunocompromised
Patients with asplenia