Pneumococcal Disease

What is pneumococcal disease?
Streptococcus pneumoniae (‘pneumococcus’) is the most common bacterial cause of community-acquired pneumonia and a common cause of bacteraemia and meningitis in children and adults. There are over 90 types of S. pneumoniae known (these are called serotypes). Disease caused by any S. pneumoniae serotypes is called pneumococcal disease.

What diseases does pneumococcus cause?
The most common types of infections caused by S. pneumoniae include:

• Middle ear infections (acute otitis media), particularly common in children
• Pneumonia
• Bacteraemia (blood stream infection)
• Sinus infections and
• Meningitis

How common is pneumococcal disease?
Pneumococcal infection is a leading cause of death worldwide. Mortality is highest in patients who develop bacteraemia or meningitis. Pneumococcal pneumonia is estimated to affect 0.1% of the population every year. Pneumococcal pneumonia is more common in smokers, heavy drinkers and those who live in over-crowded sleeping quarters.
 
Who is most at risk of pneumococcal disease?
Individuals most at risk of pneumococcal infections are usually the very young or the elderly. Those with the following conditions are particularly vulnerable and are recommended the pneumococcal vaccine:

• Persons 65 years of age or older 
• Asplenia (no spleen) or severe dysfunction of the spleen, including surgical splenectomy
• Chronic renal disease or nephrotic syndrome
• Chronic heart, lung or liver disease, including cirrhosis
• Diabetes mellitus
• Sickle cell disease
• Immunodeficiency or immunsuppression due to disease or treatment, including HIV infection at all stages
• Patients with CSF leaks, either congenital or complicating skull fracture or neurosurgery
• Individuals with cochlear implants

How do people get infected?
Transmission is from person to person, usually through respiratory droplet spread, but may be by direct oral contact or indirectly through articles contaminated with respiratory discharges. The bacteria is spread through contact between persons who are ill or who carry the bacteria in their throat (often without being ill). The incubation period (time between exposure to the bacteria and becoming ill) varies by type of infection and can be as short as one to three days.

How is pneumococcal disease treated?
Pneumococcal disease is treated with antibiotics. In recent years many pneumococci have become resistant to some of the antibiotics used to treat pneumococcal infections; high levels of resistance to penicillin are uncommon.
 
How is pneumococcal disease prevented?
Pneumococcal disease can be prevented by vaccination. Vaccination is recommended for those most at risk of disease.

Two types of vaccines against pneumococcal disease are available in Ireland

• Pneumococcal polysaccharide vaccine is a 23-valent polysaccharide vaccine (PPV23) which protects against 23 of the most common serotypes of pneumococcus. The vaccine is approximately 65% effective in preventing pneumonia.
  • This vaccine is currently recommended for use in all adults who are 65 years of age and older, as well as for anyone 2 years of age and older who is at high risk for disease (see above- Who is most at risk of pneumococcal disease?)
  • The vaccine is not recommended for children under two years of age as it does not work well in this age group
  • For some individuals at highest risk of disease (people whose antibody levels are likely to have declined more rapidly, e.g. those with no spleen, with splenic dysfunction or with nephrotic syndrome), another dose should be given five years later.
    
• Pneumococcal conjugate vaccine is a seven valent conjugate vaccine (PCV7) and protects against seven of the pneumococcal serotypes most commonly associate with disease. PCV7 is licensed for use in children up to five years of age who are considered at risk. PCV7 protects against approximately 70% of the pneumococcal infections.

Immunisation schedule, vaccine used and number of doses required will vary, depending on the age of the person to be vaccinated. The following table summarises the most recent recommendations.

Table 1. Vaccination schedule for pneumococcal vaccine for individuals at increased risk of pneumococcal disease

Booster doses are not routinely recommended once children and adults have completed the appropriate vaccination schedule, unless these individuals have antibody levels likely to decline more rapidly e.g. those with no spleen, with splenic dysfunction, nephrotic syndrome or chronic renal disease. In these circumstances re-immunisation with 23-valent polysaccharide vaccine should be given every five years.

For more information on pneumococcal vaccines please see the Immunisation Guidelines for Ireland 2008

For details on the epidemiology of pneumococcal disease in Ireland click here.

Click here to see factsheet in other languages.

Last updated: 25th January 2008