Prevnar 20
Prevnar 20
Generic Name
Prevnar 20
Mechanism
- Conjugated polysaccharides: 20 capsular polysaccharide serotypes chemically linked to the CRM197 carrier protein.
- Immune response: Induces T‑cell–dependent B‑cell activation → IgG antibody production and memory B cells.
- Protection: High avidity, opsonizing antibodies promote phagocytosis and complement fixation, reducing invasive disease.
Pharmacokinetics
- Administration route: Intramuscular (IM) injection, typically deltoid.
- Absorption: Rapid local uptake; peak antibody titers reached 2–4 weeks post‑dose.
- Distribution: Systemic circulation of antibodies; no significant tissue accumulation.
- Elimination: Antibody catabolism via reticuloendothelial system; vaccine components metabolized and cleared within days.
- Longevity: Protective antibody titers persist for ≥4 years, with booster responses upon re‑exposure.
Indications
- Routine immunization:
- Infants 2, 4, 6, 12–15 months and a booster at 12–15 months.
- Adolescents 12–15 years and adults 18–64 years at increased risk (e.g., smokers, chronic conditions).
- Target populations:
- Adults ≥65 years (recommended for all).
- Immunocompromised patients, chronic diseases, or those on immunosuppressants.
Contraindications
- Contraindicated:
- Known hypersensitivity to any vaccine component (CRM197, aluminum hydroxide, polysorbate 80).
- Warnings:
- Use caution in patients with severe acute illness or uncontrolled comorbidities.
- Not a live vaccine; safe in immunocompetent individuals.
- Potential for febrile seizures in children <6 months (rare, age‑specific risk).
Dosing
| Age Group | Dose Schedule (IM) | Interval | Note |
| 6–12 mo | 1 mL (0.5 mL/0.25 mL) | 6–12 wk | Follow 4‑dose primary series. |
| 12–15 mo | 1 mL (0.5 mL/0.25 mL) | — | Booster. |
| 12–15 y & 18–64 y | 1 mL (0.5 mL/0.25 mL) | — | Single dose. |
| ≥65 y | 1 mL (0.5 mL/0.25 mL) | — | Single dose. |
• Injection technique: 45° angle, 1 cm needle (5 mm for infants).
• Storage: 2–8 °C; protect from light; reconstitute with sterile water if supplied as freeze‑dry.
Adverse Effects
Common
• Injection‑site pain, redness, swelling (≤30 % of recipients).
• Fever (≤15 %).
• Irritability or fussiness in infants.
Serious
• Hypersensitivity reactions (anaphylaxis, angioedema) – rare (<0.01 %).
• Seizures (febrile) in children ≤6 months – exceedingly rare.
• Severe local reactions (necrotizing fasciitis) – case reports, highly unlikely.
Monitoring
- Immediate: Observe for 15–30 min post‑dose for anaphylaxis.
- Post‑vaccination:
- Fever monitoring for 48 h.
- Document injection‑site reactions.
- Long‑term: Routine clinical follow‑up; no laboratory monitoring required unless underlying disease dictates.
Clinical Pearls
- Adjuvant advantage: Aluminum hydroxide improves immunogenicity but may cause local inflammation—use smallest effective volume.
- Serotype coverage: 20 serotypes cover ≥95 % of invasive pneumococcal disease in the U.S.; inclusion of serotypes 8, 10A, 12F, and 15B/C increases protection in adults.
- Booster timing: For adults ≥65 y, a single dose is sufficient; no need for PCV13 or PPSV23 simultaneously unless indicated for specific risk factors.
- Co‑administration: Safe with other routine childhood vaccines (e.g., DTaP, Hib, IPV) when given in separate sites.
- Vaccine‑induced fever: Provide acetaminophen or ibuprofen as needed; avoid aspirin in children to reduce Reye’s syndrome risk.
- High‑risk adults: For smokers or chronic disease patients, administer as part of the 18–64 y schedule to reduce pneumonia incidence by ~30 %.
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• *Prepared with the latest CDC and EMA guidelines; for definitive protocols, refer to the manufacturer’s prescribing information.*