Overview
Pneumococcal disease is caused by the bacterium Streptococcus pneumoniae. These bacteria are the leading cause of bacterial pneumonia in young children and older people.
Introduction
There are over 90 types of Streptococcus pneumoniae that cause a range of symptoms from relatively minor to very serious. Some types are more likely to cause infections in particular parts of the body than others, such as the sinuses and the ear. Pneumococcal infections may be local or invasive.
Pneumococcal disease occurs throughout the year, but is more common in autumn and winter. Māori and Pacific children are more affected by pneumococcal disease than other ethnicities in New Zealand.
Invasive pneumococcal disease (IPD) occurs if the pneumococcal bacteria pass into the blood, resulting in a severe form of pneumonia, bacteraemia (blood infection) and meningitis, and can infect other sites around the body, including the heart muscle, joints and abdomen.
The World Health Organization (WHO) has stated that pneumococcal disease is currently the world’s number one vaccine-preventable cause of death among infants and children younger than five years of age.
Transmission
Pneumococcal bacteria are carried in the nose and throat and are easily passed from person to person by coughing, sneezing and close contact. Children are a major reservoir for infection. Many people can carry the pneumococcal bacteria without developing disease.
Symptoms
Local infection can cause ear infections (otitis media) and sinusitis that are unpleasant and painful, but not life threatening.
Invasive infection. If the pneumococcal bacteria pass into the blood, the early stages of serious pneumococcal disease may appear like influenza with general aches, pains and fever, but can progress very quickly (within hours) and almost always results in hospitalisation.
Pneumococcal pneumonia is the most common form of invasive pneumococcal disease and can be life threatening. The bacteria may be localised within the lung (non-bacteriaemic pneumonia) or spread throughout the lung and into the blood (bacteriaemic pneumonia). Pneumonia starts with a sudden fever and shaking chills, chest pain, coughing, shortness of breath and rapid breathing or grunting.
Invasive pneumococcal disease can lead to pneumococcal meningitis and bacteraemia, which are also very serious and need immediate medical attention. A baby or child with meningitis may have a fever, be irritable, refuse drinks or feeds, vomit, be sleepy or difficult to wake, dislike bright light, and may have a headache. With bacteraemia, they may have a fever and be irritable.
Treatment
Combination antibacterial medication (antibiotics) is the first line of treatment for all types of pneumococcal disease. However, the drug resistance of pneumococcal bacteria is an increasing problem, for example in the USA, three in ten cases of pneumococcal infection are now resistant to one or more antibiotics.
Supportive care is necessary and may include intravenous fluids, oxygen therapy, and maintenance of hygiene and comfort to prevent pressure sores.
Risks
Being exposed to cigarette smoke, living in crowded conditions, and/or having some medical conditions can also increase the risk of pneumococcal disease.
People with medical conditions that affect their immune system have an increased risk of infection, such as those without a functioning spleen, and those who have a weakened immune system from disease or treatment of a disease.
Ear infections are painful and complications can lead to deafness, often compounding into learning difficulties during childhood.
Pneumococcal meningitis is very serious, one quarter to half of the children affected will have long-term disabilities.
Pneumococcal infections can be difficult to treat, particularly in cases of antibiotic resistance.
Healthy children under 5 years of age and the elderly are at higher risk from pneumococcal disease. The highest risk of serious disease is in infants less than one year of age, Māori, Pacific Peoples and older people. The risk of invasive pneumococcal disease for Māori is just over three times, and for Pacific Peoples almost four times, higher than the risk for NZ Europeans.
Prevention
Vaccination of infants, the elderly and those at increased risk due to underlying medical conditions can help to prevent pneumococcal disease and bacterial spread. Pneumococcal conjugate vaccines are available that help to protect against 10 to 13 strains of Streptococcus pneumoniae. Vaccination of all infants also helps to protect other age groups by reducing the carriage and spread of certain strains of the bacteria in children, this is known as ‘herd’ or ‘community’ immunity’. A polysaccharide vaccine is also available for use from the age of 2 years which provides broad protection against 23 serotypes of S. pneumoniae.
It is difficult to avoid coming into contact with such a common bacteria, but good hygiene practices, covering coughs and sneezes, hand washing, avoiding smoking and reducing overcrowded living conditions can help reduce spread.
Babies born to mothers who have high levels of pneumococcal antibodies may have some protection from the disease at birth. However, by two months of age almost one third of the maternal antibodies have gone and will have virtually disappeared by the age of seven months. Without vaccination, infants cannot develop their own effective protection against pneumococcal bacteria until about two years of age.
