Tuesday, March 21, 2017

Pneumococcal vaccine: Which, when, and why?

The pneumococcal vaccine was developed to reduce the disease burden of streptococcus pneumoniae, a gram-postive bacteria that has more than 90 serotypes that can cause diseases in humans.  Some of these infections include pneumonia, meningitis, bacteremia, otitis media, and sinusitis.  There are currently two vaccines on the market to raise immunity against pneumococcal infections - PCV13 (Prevnar 13 - which covers 13 serotypes) and PPSV23 (Pneumovax 23 - which covers 23 serotypes).  The 23-valent vaccine covers all of the serotypes in the
13-valent product except for one (serotype 6A is only in the 13-valent product).  We'll look at which vaccine is appropriate in a given scenario and when to give them and what to do when the patient needs both - but only in adults.


One important concept at this point is "high risk" patients.  These are patients who are functionally or anatomically asplenic, immunocompromised, or have CSF leaks or cochlear implants.  "Immunocompromise" also needs some further clarification.  In the case of pneumococcal vaccine indications, it refers to the following conditions:

  • Congenital or acquired immunodeficiency
    • B- and T-lymphocyte deficiencies
    • Complement deficiencies
    • Phagocytic disorders
  • HIV
  • Chronic renal failure and nephrotic syndrome
  • Leukemia, lymphoma, Hodgkin disease, malignancy, multiple myeloma
  • Solid organ transplant
  • Iatrogenic immunosuppression


Which vaccine to give

PCV13 (Prevnar 13) - ONE maximum lifetime adult dose
  • If a patient is 19-64 years old and is not high risk, they don't need it
    • If they are "high risk" (see above), then they should receive it
  • Give to all adults ≥65 years old, even if they are healthy (but only if they never received it as an adult)

PPSV23 (Pneumovax 23) - up to THREE lifetime doses
  • Only give to 19-64 years old if they have certain medical conditions ("high risk" above OR chronic heart, liver, or lung disease, diabetes mellitus, alcoholism, cigarette smoker)
    • Asplenia and immunocompromised should get a booster once after 5 years
  • Give to all adults ≥65 years old, no matter medical history, as long as it's been 5 years
    • Never revaccinate after this


What if they need both

If the patient is indicated to receive both, you always give PCV13 first
  • If they already received PPSV23, first wait 1 year
  • How long you wait to give PPSV23 (after PCV13) depends on age and comorbidity
    • If there's no urgency (ie. routine ≥65 years old or chronic medical conditions), wait 1 year
    • If they're "high risk", only wait 8 weeks


Here is an illustration that may help:

(click to enlarge)

Benefit of vaccination

Pneumococcal vaccinations have been shown to reduce the risk of invasive disease (eg. bacteremia, meningitis).  What has not consistently been shown, unfortunately, is reduced rates of pneumococcal pneumonia.  That doesn't mean that there is no benefit related to pneumonia.  Patients that get pneumonia that were previously vaccinated do benefit from:
  • Fewer pneumonia-related complications
  • Decreased length of hospital stay
  • Decreased need for ICU admission
  • Lower mortality

References
Centers for Disease Control and Prevention.  Recommended immunization schedule for adults aged 19 years or older, by vaccine and age group.  Available at: https://www.cdc.gov/vaccines/schedules/hcp/imz/adult.html  Accessed March, 2017

photo and image by HughesMedicine

2 comments:

  1. Pneumococcal vaccines are now available that is a very good news as toddlers and old age people have the highest risk of suffering from pneumonia.

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