CLINICARE PHARMACISTS
Pneumococcal vaccination in adults By Julianna Fang, B.Sc. (Pharm.), R.Ph., CDE, Larry Leung, B.Sc. (Pharm.), R.Ph., and Jason Min, B.Sc. (Pharm.), R.Ph. Pharmacists are getting busier every year providing an increasing number of immunizations to patients. Just as we help patients make informed decisions when managing their drug therapy, it’s important that we do the same when it comes to vaccinations. We have recently received more questions regarding the pneumococcal conjugate vaccine 13-valent (PCV13, Prevnar 13) and the difference between it and the other publicly-funded pneumococcal polysaccharide vaccine 23-valent (PPV23, Pneumovax 23). We had a patient come to us who had heard about Prevnar 13 and wondered which vaccine would be better for her. The patient: • 68-year-old female, NKDA. • PMHx: COPD, hypertension, atrial fibrillation — all well controlled. • Medications: budesonide/formoterol 200mcg one puff twice daily, ramipril 10mg od, hydrochlorothiazide 12.5mg od, apixaban 5mg twice daily, diltiazem CD 240mg od . • Past immunizations: influenza annually. PCV13 covers 13 strains of Streptococcus pneumoniae and contains polysaccharides conjugated to a diphtheria protein carrier. This conjugation allows for a T-cell mediated immune response, which results in longer immunological memory. PPV23 on the other hand covers 12 of the same strains as PCV13, and 11 additional strains. It is a polysaccharide vaccine that interacts directly with B cells, resulting in shorter immunological memory. In BC, about 25% of invasive pneumococcal disease (IPD) cases are due to strains common to both vaccines, and 34% of cases are due to strains covered only by PPV23. Since 2013, the National Advisory Committee on Immunization (NACI) has recommended PCV13 for adults of any age if they are immunocompromised. This is based on evidence suggesting improved efficacy and immunogenicity. This includes hematopoietic stem cell transplant (HSCT) and HIV-positive patients. The NACI concluded there was insufficient evidence to recommend PCV13 for healthy elderly or populations with other chronic conditions (e.g. diabetes, kidney disease).
In BC, PCV13 has long been publicly-funded for routine immunization of children under five, asplenics up to age 18 and HSCT patients. As of April 2015, the BC Centre for Disease Control (BCCDC) expanded coverage of PCV13 to include HIV patients. When PCV13 is being used in this population the recommended schedule is one dose of PCV13, followed by a second dose of PPV23 in eight weeks. Neither guideline from the NACI nor BCCDC provided strong recommendations on PCV13 use in elderly patients with chronic conditions, so we conducted a literature search for more current evidence. One study in patients over the age of 65 found significantly higher immunogenicity after PCV13 vaccination for 10 of the 12 strains common to both vaccines, and non-inferior immunogenicity for the remaining two common strains. Another study examined efficacy of PCV13 in patients over age 65 with chronic conditions, excluding immune-suppression, and found a vaccine efficacy of 45% for prevention of community-acquired pneumonia, and 75% for prevention of IPD (septicemia, meningitis, etc.). Comparatively, a Cochrane review of polysaccharide pneumococcal vaccines suggested efficacy for prevention of IPD but not for pneumonia or mortality. Safety data suggests similar risks for common adverse effects such as localized reactions, fever and malaise for both vaccines. After discussion with the patient, we agreed that given her age and comorbidities, she is at relatively higher risk for pneumococcal disease. Some recent evidence suggests PCV13 may provide improved immunologic response and protection against pneumonia, with no increased risk, compared to PPV23 in elderly patients with chronic conditions. However, Canadian guidelines still do not recommend PCV13 over PPV23 in this population as there is not enough proof of additional benefit. Based on this, we recommended she receive PPV23. Julianna Fang is a practicing clinician with Clinicare Pharmacists Inc. and a community pharmacist. She is committed to continued learning, and passionate about improving patient care through patient education and interdisciplinary collaboration. References available upon request at info@bcpharmacy.ca.
www.bcpharmacy.ca
Jan/Feb 2016
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