Causative Agent
Streptococcus pneumoniae is the bacterium responsible for causing
pneumococcal infection. It is characterised by its outer coat (capsular polysaccharide),
and in a process known as serotyping, different strains can be distinguished.
There are about 90 different types of pneumococci, and about a quarter of which
cause serious illness.
Clinical Description
Pneumococcal infections are defined as invasive or non-invasive according
to the body site they affect. Invasive pneumococcal disease (IPD) is caused
by infection of normally invasive sites e.g. blood and cerebrospinal fluid (CSF). IPD is a major cause of morbidity and mortality, especially amongst the
very young, the elderly, and those with impaired immunity. Non-invasive forms
of the infection commonly cause middle ear infection (otitis media), exacerbations
of bronchitis, and pneumonia. As with most infectious respiratory diseases,
the numbers of cases of pneumococcal infection peak in winter.
Transmission
As a commonly carried pathogen. The role of person to person transmission
is unclear. Many people (up to 50%) carry pneumococci in their nose and throat
without developing serious infection.
Surveillance in Scotland
IPD is not a statutorily notifiable disease, therefore surveillance is based
on the local and reference laboratory reports of S. pneumoniae from
invasive body sites (i.e. blood and CSF mainly). In 1999, an enhanced surveillance
scheme was introduced, and is jointly managed by HPS and the Scottish Meningococcus
and Pneumococcus Reference Laboratory (SMPRL).
Trends in Scotland (2000-2010)
In 2010 there were 540 cases of invasive pneumococcal disease reported to SPIDER, this compares to 579, 606 and 629 cases in 2009, 2008 and 2007 respectively.
Annual reports of invasive pneumococcal disease in Scotland by year
| Year |
Reported IPD cases |
2000 |
559 |
2001 |
597 |
2002 |
614 |
2003 |
790 |
2004 |
631 |
2005 |
719 |
2006 |
753 |
2007 |
629 |
2008 |
606 |
2009 |
579 |
2010 |
540 |
| |
|
Since the introduction of pnuemococcal conjugate vaccine in 2006, there has been a reduction in the number of cases reported in the under 5s, with 95 cases in 2005, 61 cases in 2006, 26 cases in 2007, 34 cases in 2008, 39 cases in 2009 and 28 cases in 2010.
Cases of IPD reported to SPIDER by quarter and by age group 1999-2011*
Prevention
Two pneumococcal vaccines are available that help to protect against pneumococcal
disease.
The pneumococcal polysaccharide vaccine is recommended for many of the same
people who receive an annual flu vaccination. Unlike the flu vaccine which is
given every year, the pneumococcal vaccine is only usually given once. The Scottish
Executive introduced pneumococcal immunisation for all people aged 65 years
and over, and for those aged under 65, at increased risk of disease due to impaired
immunity in the season 2003/2004. This vaccine protects against 23 serotypes
of IPD.
Pneumococcal conjugate vaccine (PCV-7) was introduced into the routine childhood immunisation schedule in September 2006. In spring 2010, PCV-7 was replaced with PCV-13 to provide broader protection against more serotypes of S. pneumoniae. The new vaccine follows the same three dose immunisation schedule at two and four months of age followed by a booster at 12-13 months. PCV-13 offers protection against the following 13 serotypes of S. pneumoniae: 1, 3, 4, 5, 14, 6A, 6B, 7F, 9V, 18C, 19A, 19F and 23F.
Vaccine uptake
Cumulative number of IPD cases reported to SPIDER 2004-2011*
Further Information
Public Health etc (Scotland) Act
The Public Health etc (Scotland) Act 2008 provides a statutory framework for public health action to protect the people of Scotland from infectious disease, contamination and other such hazards.
Under the Act Streptococcus pneumonia (from blood, cerebrospinal fluid or other normally sterile site) is a notifiable organism.
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