Pneumococcal disease

From the Australian government
Pneumococcal disease refers to a wide range of infections caused by the bacterium Streptococcus pneumoniae. The most severe infections, bacteraemia (a blood stream infection) and meningitis (inflammation of the membranes enclosing the brain), are a leading cause of life-threatening illnesses in Australia – particularly among children under two years of age and elderly people.
Some types of Streptococcus pneumoniae are commonly found in the upper respiratory tract (nose, throat and windpipe) of healthy people. As well as meningitis and bacteraemia, pneumococcal disease can cause pneumonia (lung infection), septicaemia (blood poisoning), and middle ear and sinus infections.
The pneumococcus bacteria can spread between people through infected droplets in the air and by touching an infected person. It most commonly spreads when an infected person sneezes or coughs.
Vaccination can substantially reduce the risk of infection with pneumococcal disease, particularly in young children. Pneumococcal vaccination is recommended as part of routine immunisation for people who face a high risk from pneumococcal and its complications. The pneumococcal vaccine is available free under the National Immunisation Program Schedule.
Source: Pneumococcal disease
The other side
Pneumococcal disease is defined as any illness caused by the bacterium Streptococcus pneumoniae. The vaccine that targets these bacteria is called the “pneumococcal conjugate” vaccine.
As you can see from the government’s information above, these bacteria can be involved in a number of illnesses, including meningitis, pneumonia, and septicaemia (blood poisoning).
The pneumococcal conjugate vaccine is one of 3 vaccines now used in Australia to combat, respectively, 3 bacterial diseases that can all cause these illnesses. These bacteria were deemed the most common causes of these conditions at the time of introduction of the respective vaccines.
The 3 bacterial diseases, the vaccine and year of introduction of the vaccine are:
- Haemophilus Infuenzae type b (Hib vaccine) – 1992-3
- Neisseria meningitidis (Meningococcal C vaccine) – 20003
- Streptococcus pneumoniae (Pneumococcal vaccine) – 2005
While these bacteria can be linked with illnesses such as meningitis, septicaemia and pneumonia, over 90% of us will play host to the range of bacteria that can cause these conditions without ever showing symptoms of any disease. We have lived with these bacteria for thousands of years and it is only in rare instances that they can make us ill.
Medicine has not sought to discover what the triggers are for turning a normally benign bacteria into a killer. Instead, its answer has been to vaccinate us against the bacteria using a shot whose side effects include suppression of our immune system, leaving us potentially more susceptible to diseases such as meningitis and septicaemia.
Disease naming and vaccine evaluation
The naming of diseases by microbe rather than by clinical symptoms is a departure from traditional disease naming, and it began during in the 1990s as pathology testing became more widely available.
A problem with evaluating the success of eradication programs of diseases named in this way is that the microbes may be wiped out by intervention measures, but that does not necessarily mean the target disease (e.g. meningitis) is wiped out. This is because other microbes can easily take the place of the ones no longer in circulation, and cause just as much disease, or even more (think of how antibiotics have bred super bugs).
Thus the only way to really evaluate success of vaccination programs of these types of diseases is to look at data for the target illness, rather than for the microbe. Despite this, health authorities continue to publish data showing reductions in disease cases caused by the Hib bacterium, suggesting vaccination for Hib has been a success.
Of the 3 diseases/vaccines listed above, only Hib has been used for long enough to evaluate its success in reducing target illnesses, but the graphs below do show some short-term results for the other two vaccines. It appears the Hib vaccine did nothing to reduce meningitis and septicaemia, and the other two vaccines didn’t help either (all-ages graphs don’t show better results for the vaccines).


Graphs are from Fooling Ourselves: on the fundamental value of vaccines by Greg Beattie
Pneumococcal disease
There is no long-term data yet for determining success or failure of the vaccine for pneumococcal disease in Australia, in terms of the target illnesses. As there are so many strains and species of bacteria around, it would be reasonable to assume that as the bacteria are eradicated, other microbes will step up to the plate and cause just as much meningitis and so on, as long as children are susceptible.
In 2008, two high profile Indian paediatricians published a letter in the Bulletin of the World Health Organisation. They discuss the merits of the pneumococcal conjugate vaccine, and point out that although it may have an effect on “vaccine-serotype bacteraemic” pneumonia, it does not reduce clinical pneumonia. In other words, regardless of what is reported about the vaccine’s effectiveness against the microbe, it does not reduce the amount of actual illness.
Source: Incidence of pneumonia is not reduced by pneumococcal conjugate vaccine; Sona Chowdhary, Jacob Puliyel. Bull WHO vol.86 no.10 Oct 2008
Vaccine decisions
The vaccine designed to protect against Streptococcus pneumoniae bacteria is known as the “pneumococcal conjugate” vaccine and the commercial name for the vaccine currently given in Australia is Prevenar 13 (spelled either Prevenar or Prevnar).
There are many thousands of strains of Streptococcus pneumoniae bacteria, and at this time around 90 serotypes have been identified world-wide (which means that although there are thousands of strains, they are detected as only 90 distinct types by our immune system).
The Prevenar 13 vaccine protects against just 13 of these 90 or so serotypes. There is certainly the potential that as the 13 serotypes addressed by the vaccine are stopped from circulatiing, other serotypes will become dominant, causing as much disease, as this is what happens with bacteria.
This vaccine is given to babies at 2, 4 and 6 months of age.
When deciding whether to vaccinate your child, it is a good idea to read product information from the manufacturers.
We suggest you look carefully at ingredients of the vaccines, contraindications and possible side effects. Also have a look at safety studies, and notice the number of subjects and follow-up time period.
DATA SHEETS
Further reading
We suggest you get hold of this excellent book – it is available as a printed book and also as a PDF and has an emphasis on Australia. See chapter 6 for a discussion of the 3 vaccines mentioned on this page.
Fooling Ourselves: on the fundamental value of vaccines by Greg Beattie
Streptococcus pneumoniae has 90 serotypes (source):
Pneumococcal Disease (WHO)
See the following page on this website: Hib (Haemophilus influenzae type b) for more discussion of bacterial diseases.