A. Pneumococcal Infection
1. What is pneumococcal infection?
Pneumococcal infection represents a wide range of diseases caused by the bacterium Streptococcus pneumoniae (or more commonly referred as pneumococcus). While pneumococcus is a common cause of mild illnesses such as sinus or middle ear infections, it may also cause severe or even life-threatening invasive pneumococcal diseases (IPD) such as bacteremic pneumonia, sepsis, and meningitis. The outcomes for IPD are usually more severe among young children and elderly persons.
2. What is Streptococcus pneumoniae / pneumococcus?
Streptococcus pneumoniae (pneumococcus) is the causative agent of pneumococcal infections. It is a Gram-positive bacterium encapsulated with polysaccharides. The difference in the composition of capsular polysaccharides constitutes to at least 90 different serotypes of pneumococci identified thus far.
3. How does individual acquire pneumococcal infections? What is the route of transmission for pneumococci?
Pneumococci are carried on human bodies. They are present in the upper respiratory tracts even in some healthy carriers. The bacteria can be transmitted via spread of droplet, direct oral contact or indirect contact with articles soiled with respiratory discharges.
4. What is the incidence rate of invasive pneumococcal diseases (IPD) in Hong Kong?
In Hong Kong, the annual incidence of IPD ranged from 1.7 to 2.9 per 100,000 from 2009 to 2019. The incidence is higher in children younger than 5 years of age and adults 65 years of age and older.
5. How can pneumococcal infections be treated?
The treatment of pneumococcal infections usually involves the use of antibiotic(s). But there is a problem of increasing resistance of the bacterium to antibiotics, which makes prevention of pneumococcal infections important
6. Is a person previously contracted with pneumococcal disease immune from future invasive pneumococcal diseases?
As there are over 90 serotypes of pneumococcus, previous infection of a serotype of pneumococcus may not confer immunity to other serotypes of pneumococcus.
7. How can invasive pneumococcal diseases be prevented?
Pneumococcal vaccination is one of the most effective means of preventing pneumococcal diseases. The public should also maintain good personal and environmental hygiene practices, balanced diet, regular exercise, adequate rest, and no smoking.
8. What is the relationship between influenza and pneumococcal infection?
Influenza predisposes individuals to community-acquired bacterial pneumonia. Secondary bacterial pneumonia has been an important cause of morbidity and mortality for those infected with influenza.
B. Pneumococcal Vaccine
1. Are there different types of pneumococcal vaccines?
There are different types of pneumococcal vaccines available in the market, such as 13-valent pneumococcal conjugate vaccine (PCV13), 23-valent pneumococcal polysaccharide vaccine (23vPPV) etc. 23vPPV consists of pneumococcal capsular polysaccharides for 23 pneumococci serotypes. PCV consists of pneumococcal capsular polysaccharides conjugated to carrier proteins.
2. What is the difference between 23-valent pneumococcal polysaccharide vaccine (23vPPV) and 13-valent pneumococcal conjugate vaccines (PCV13)?
PCV13 is effective against both invasive pneumococcal disease and non-invasive pneumococcal pneumonia. On the other hand, while clinical studies indicated that 23vPPV is generally effective in preventing IPD, its efficacy against non-invasive pneumococcal pneumonia is suboptimal. Nevertheless, it is worth noting that 23vPPV contains more serotypes and theoretically offers extra protection.
3. Who should get pneumococcal vaccines?
The Scientific Committee on Vaccine Preventable Diseases (SCVPD) recommends children under 2 years of age to receive pneumococcal conjugate vaccines (PCV) under the Hong Kong Childhood Immunisation Programme (HKCIP). The standard regimen includes a primary series of 2 doses at 2 and 4 months and a booster dose at 12 months.
SCVPD recommends high-risk individuals* aged 2 years or above to receive a single dose of 13-valent pneumococcal conjugate vaccine (PCV13), followed by a single dose of 23-valent pneumococcal polysaccharide vaccine (23vPPV) 1 year later. For those who have already received 23vPPV, a single dose of PCV13 should be administered 1 year after previous 23vPPV vaccination. For those who have already received PCV13, a single dose of 23vPPV should be administered 1 year after previous PCV13.
For elderly 65 years of age and older without high-risk conditions*, SCVPD recommends either a single dose of PCV13 or a single dose of 23vPPV.
*High-risk conditions include:
(a) History of invasive pneumococcal disease
(b) Immunocompromised states:
- Asplenia, HIV /AIDS , primary immunodeficiency
- Immunodeficiencies related to malignancies and transplantation
- Immunodeficiencies related to use of immunosuppressive drugs / systemic steroid
(c) Chronic disease
- Chronic cardiac, pulmonary, liver or renal disease
- Diabetes mellitus or Cerebrospinal fluid leakage
(d) With cochlear implants
(Essential hypertension per se is not considered as a high-risk condition)
Different factors such as age and clinical condition may affect the risk of pneumococcal disease. Patients with high-risk conditions should discuss with their attending doctors on the most appropriate vaccination regimen.
Remarks: Under the Government Vaccination Programme and Vaccination Subsidy Scheme, aside from the above list of high-risk conditions, elders 65 years or above with chronic metabolic diseases, obesity (BMI 30 or above), chronic neurological conditions or those with financial difficulties are eligible for free/subsidised pneumococcal vaccination. Please see annex for the list of high-risk conditions eligible for free / subsidized PCV 13 under Government Vaccination Programme and Vaccination Subsidy Scheme.
4. Why is it necessary for elders to receive both influenza vaccine and pneumococcal vaccines?
Secondary bacterial pneumonia is an important cause of morbidity and mortality for those infected with influenza. Data from a local study shows that dual vaccination with influenza vaccine and pneumococcal vaccines can lower the risk of hospitalisation and mortality among elderly people.
5. Can pneumococcal vaccines be received together with seasonal influenza vaccine?
Yes. Both 23-valent pneumococcal polysaccharide vaccine (23vPPV) and pneumococcal conjugate vaccines (PCV) can be given together with other vaccines, including influenza vaccine, but they should be administered with a different syringe and at a different injection site.
6. Can pneumococcal vaccine be given together with COVID-19 vaccine?
There are currently limited data on the simultaneous administration of COVID-19 vaccines with other vaccines. It is suggested to have a minimal interval of at least 14 days between administration of COVID-19 vaccine (Comirnaty or CoronaVac) and any other vaccine.
7. Can pneumococcal vaccines be given prior to / after certain medical procedures?
For individuals who will undergo elective splenectomy, pneumococcal vaccines should be given at least 2 weeks before the procedures if possible. Pneumococcal vaccines should ideally be given before or after completion of chemotherapy/radiotherapy but they may still be given as clinically indicated during long term use of chemotherapeutic agents.
8. What are the possible adverse reactions following 23-valent pneumococcal polysaccharide vaccine administration (23vPPV)?
23vPPV has been demonstrated to be safe. Common adverse reactions include slight swelling and tenderness at the injection site shortly following injection but most resolve within two days. Fever, muscle aches or more severe local reactions are uncommon.
9. What are the possible adverse reactions following pneumococcal conjugate vaccine (PCV) administration?
PCV has been demonstrated to be safe. Common adverse reactions include slight swelling and tenderness at the injection site shortly following injection but most resolve within two days. Some may experience mild fever, fatigue, headache, chills, or muscle pain. Severe pain or difficulty in moving the arm where the shot was given was very rare.
10. Who are not suitable to receive pneumococcal vaccines?
Severe allergic reaction following a prior dose of pneumococcal vaccine or to the vaccine component or any diphtheria toxoid-containing vaccine is a contraindication to further doses of vaccine.
11. Can individual receive pneumococcal vaccines if they are not feeling well on the day of vaccination?
Minor illnesses such as upper respiratory tract infections are not contraindications to vaccination. Vaccination may also be deferred until symptoms subside in case of any worry.
12. Can 13-valent pneumococcal conjugate vaccine (PCV13) administered other than intramuscularly?
PCV13 should be administered intramuscularly. This vaccine should not be given to individuals with thrombocytopenia or any coagulation disorders that would contraindicate intramuscular injection unless the potential benefit clearly outweighs the risk of administration.
Do not administer PCV 13 intravascularly or into the gluteal area. Do not administer PCV13 intravenously, subcutaneously or intradermally, since the safety and immunogenicity of these routes have not been evaluated.
Please refer to the drug insert for detailed information.
C. Schedule for Pneumococcal Vaccination to Elders
1. What is the interval between 23-valent pneumococcal polysaccharide vaccine (23vPPV) and 13-valent pneumococcal conjugate vaccines (PCV13)?
According to the recommendation of SCVPD, the recommended interval between 23vPPV and PCV13 should be 1 year.
2. Should high-risk elders receive 2 doses of 23-valent pneumococcal polysaccharide vaccine (23vPPV) instead of 1 dose of 13-valent pneumococcal conjugate vaccines (PCV) and 1 dose of 23vPPV?
No. High-risk individuals aged 65 years and above should receive one dose of PCV13 and one dose of 23vPPV.
3. Should high-risk elders receive 2 doses of 13-valent pneumococcal conjugate vaccines (PCV13) instead of 1 dose of PCV13 and 1 dose of 23-valent pneumococcal polysaccharide vaccine (23vPPV)?
No. High-risk individuals aged 65 years and above should receive one dose of PCV13 and one dose of 23vPPV.
4. Should high-rish elders receive 13-valent pneumococcal conjugate vaccines (PCV13) if they have already received 2 doses of 23-valent pneumococcal polysaccharide vaccine (23vPPV)?
Yes, they should receive a single dose of PCV13 one year after the last dose of 23vPPV vaccination.
5. How can elders confirm their previous pneumococcal vaccination history?
Elders should try to find out all their previous vaccination records/cards and bring them to their attending doctor. Vaccination records are important reference to doctors before they can provide appropriate vaccination. Else, elders should return to the clinics where they received previous vaccinations to trace their records. If they still cannot trace the records, they should tell their doctors their vaccination history as far as they can recall so that their doctor can make assessment and provide them with the necessary vaccination.
6. If elders with high-risk conditions are not sure if they have previously received pneumococcal vaccine (type and time), should they still go for vaccination?
Yes. If elders with high-risk conditions do not have a documented vaccination history (vaccination card and electronic record) for pneumococcal vaccine, they should trace record from clinics receiving previous dose of pneumococcal vaccine. If the elders still cannot trace the record and cannot recall the type and time of vaccination, they should still receive the recommended doses, i.e. a single dose of PCV13 followed by a dose of 23vPPV one year later.
7. Can elders with high-risk conditions choose to have 23-valent pneumococcal polysaccharide vaccine (23vPPV) vaccination first?
SCVPD recommends individuals with high-risk conditions who have not received any pneumococcal vaccines to receive one dose of PCV13 followed by 23vPPV one year later. For advice on individual cases, elders should consult their family doctor.
8. If elders have received 23-valent pneumococcal polysaccharide vaccine (23vPPV) before, do they need revaccination of pneumococcal vaccine?
For elders who have previously received 23vPPV before, if they do not have risk factors for IPD, no further pneumococcal vaccination is needed. If they have risk factors for IPD, they should receive one dose of PCV13 one year after the previous 23vPPV.
9. If elders have received 13-valent pneumococcal conjugate vaccines (PCV13) before, do they need revaccination of pneumococcal vaccine?
For elders aged 65 years or above, who have previously received one dose of PCV13 before, if they do not have risk factors for IPD, no further pneumococcal vaccination is needed. If they have risk factors for IPD, they should receive one dose of 23vPPV one year after the previous PCV13.
Annex: List of high-risk conditions eligible for receiving free / subsidized 13-valent pneumococcal conjugate vaccine (PCV13) under Government Vaccination Programme and Vaccination Subsidy Scheme 2021/22
Source: Centre for Health Protection
last update：9 Sept 2021
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