肺炎球菌

什么是流行性感冒？

Pneumococcal disease is caused by infection with the bacteria 肺炎链球菌 (pneumococcus), which can live in the nose and throat (nasopharynx). In most cases it is considered part of the normal flora and generally does not cause illness or disease. However, in some cases the bacteria may grow and spread to other parts of the body that would normally be sterile, causing invasive pneumococcal disease (IPD), severe infections and complications. The bacteria can also cause non-invasive pneumococcal disease (non-IPD), for example, conjunctivitis and pneumonia.

There are more than 95 different recognised serotypes of 肺炎链球菌 that have a distinct polysaccharide capsule (encapsulated strains). The capsule protects the bacteria from being easily destroyed by the body’s immune system. Encapsulated strains are almost exclusively the cause of IPD. Non-encapsulated strains can also cause IPD; however, this is more likely in immunocompromised individuals. 

流感症状

The incubation period of pneumococcal disease is 1 to 3 days.

症状 will vary depending on the site of infection and can include:

• 发烧 
• headaches and sinus pain 
• earache 
• cough and coryza (runny nose). 

Clinical signs and symptoms of pneumococcal disease cannot be distinguished from other bacterial infections without laboratory testing.

Pneumococcal infection can lead to sinusitis, otitis media (ear infections) and pneumonia (lung infections). Sometimes infection can result in meningitis (inflammation of the tissue surrounding the brain and spinal cord), pneumonia with empyema (pus collection), septicaemia (blood infection), osteomyelitis (bone infection) and joint infections. IPD can have long-term consequences, such as hearing loss, kidney failure, loss of limbs or intellectual disability.

结核病是如何传播的？

Pneumococcal is spread by direct contact with the respiratory droplets (e.g. saliva or mucus) produced from coughing or sneezing, for example. Contact with contaminated items such as tissues can also be a source of infection.

Pneumococcal bacteria can live harmlessly at the back of the nose or throat (asymptomatic nasopharyngeal colonisation). This means individuals can be asymptomatic carriers and may transmit the bacteria to others without knowing. Between 20–40% of children and 5–10% of adults are asymptomatic carriers of pneumococcal bacteria. Whether the presence of pneumococcal bacteria leads to IPD depends on the virulence of the specific serotype and the individual’s immune response.

The infectious period is presumed to last until secretions no longer contain the bacteria in significant numbers, or for 24 to 48 hours after commencing antibiotics. Note that some strains of pneumococci bacteria are resistant to antibiotics.

流行病学

Pneumococcal disease is a leading cause of serious illness and death among Australian children under 2 years of age and older people. Aboriginal and Torres Strait Islander children in central Australia have the highest reported rates of IPD worldwide.  

The introduction of vaccines has led to large decreases in pneumococcal disease incidence. Despite this, the global burden remains significant; it is estimated that around one million people die from pneumococcal disease worldwide every year. Much of the IPD burden results from serotypes not targeted by current vaccines. 

Immunocompromised individuals, (such as people with functional asplenia or people taking immunosuppressant medications) and individuals with congenital heart disease, are at the highest risk of IPD. A full list of at-risk conditions can be found in The Australia Immunisation Handbook: Risk conditions for Pneumococcal Disease.

Prevention

There are two pneumococcal vaccines currently available on the National Immunisation Program (NIP) in Australia: 

• Prevenar 13 is a conjugate vaccine (13vPCV), providing protection against 13 different serotypes of pneumococcal (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 23F). It is available on the NIP for individuals 6 weeks of age and older 
• Pneumovax 23 is a polysaccharide vaccine (23vPPV), providing protection against 23 serotypes of pneumococcal (1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F and 33F). It is available on the NIP as an additional recommendation for individuals over 4 years who are at increased risk of IPD (it is not recommended for those under 2 years due to poor immunogenicity in this population).  

Both these vaccines are administered intramuscularly.

§ If under 5 years and not up to date with NIP recommendations, refer to The Australian Immunisation Handbook for 13vPCV catch up advice
Ω No more than 4 lifetime doses of 13vPCV
^ If 23vPPV is inadvertently given prior to required dose of 13vPCV, wait 12 months before administering 13vPCV
Σ No more that 2 lifetime doses of 23vPPV
β 23vPPV must be minimum of 8 weeks after last dose of 13vPCV.
Grey shaded boxes not registered for use in this age group.

Co-administration with other vaccines

肺炎球菌 vaccines can be co-administered with other vaccines on the NIP.

疫苗副作用 

Common side effects after receiving a pneumococcal vaccine include fever, irritability, lethargy, injection site reactions (ISRs) and body aches. 

In children, ISRs are commonly reported as occurring within 24 to 48 hours following immunisation. In adults, Prevenar 13 is associated with delayed-onset ISRs (occurring more than 3 days after vaccination), particularly in those who have previously received Pneumovax 23. 

ISRs are not a sign of allergy or local infection. Therefore, antihistamines, steroids or antibiotics are not required. 
A history of ISRs following previous pneumococcal vaccines is not a contraindication to further doses. 

Refer to the MVEC：注射部位反应 reference page for further information. 

资源

• Australian Immunisation Handbook: Pneumococcal disease 
• Australian Immunisation Handbook: List. Risk conditions for pneumococcal disease 
• MVEC: Catch-up immunisations
• Human Vaccines and Immunotherapeutics: Coadministration of 13-valent pneumococcal conjugate and quadrivalent inactivated influenza vaccines in adults previously immunized with polysaccharide pneumococcal vaccine 23: a randomized clinical trial