PPSV23 Effectiveness After Herceptin (Trastuzumab)
Yes, PPSV23 can be effective when given 6 weeks after Herceptin, though the optimal timing depends on the patient's immunocompromised status and prior pneumococcal vaccination history.
Key Considerations for Timing
The 6-week interval you're asking about falls within acceptable vaccination windows for immunocompromised patients, though specific guidance varies by clinical context:
For Immunocompromised Patients (Including Cancer Patients on Biologics)
If the patient has received PCV (PCV13, PCV15, or PCV20) previously: PPSV23 should be administered ≥8 weeks after the PCV dose for patients with immunocompromising conditions 1.
Six weeks (approximately 42 days) is slightly shorter than the recommended 8-week minimum interval for immunocompromised patients, though this represents a minor deviation that may still provide benefit 1.
For solid organ transplant recipients, PPSV23 is recommended 2-6 months post-transplant, with timing based on degree of immunosuppression, and ≥8 weeks after indicated PCV13 doses 1.
Immunogenicity Concerns with Herceptin
Trastuzumab (Herceptin) is not typically classified as causing severe immunosuppression like chemotherapy or high-dose corticosteroids, but cancer patients may have compromised immune responses:
Studies show that patients on immunosuppressive therapy have impaired vaccination responses, with seroprotection rates of 44-58% compared to 82% in controls 2.
However, PPSV23 vaccination remains immunogenic even in immunosuppressed patients, though responses may be blunted 2, 3.
Optimal Vaccination Strategy
The preferred approach for cancer patients depends on their pneumococcal vaccination history:
If Pneumococcal Vaccine-Naïve:
- Administer PCV20 as a single dose rather than PPSV23 alone 4, 5.
- If PCV20 unavailable, give PCV15 followed by PPSV23 ≥8 weeks later for immunocompromised patients 1, 5.
If Previously Received PCV13/PCV15:
- PPSV23 can be given ≥8 weeks after the PCV dose for immunocompromised patients 1.
- Your 6-week interval is 2 weeks shorter than ideal but may still provide benefit, particularly if the patient is not severely immunosuppressed 1.
If Previously Received PPSV23 Only:
Evidence on Sequential Vaccination
Multiple studies demonstrate that PPSV23 following PCV vaccination is immunogenic:
Sequential PCV13 followed by PPSV23 at intervals of 2,6, or 12 months all showed robust immune responses without evidence of hyporesponsiveness 1, 6.
In studies where PPSV23 was given 1-2 months after PCV13 in HSCT recipients, immune responses were comparable to initial PCV doses for shared serotypes 1.
Shorter intervals between PCV and PPSV23 (as short as 1 month) have been studied and shown to be immunogenic, though current guidelines recommend longer intervals for optimal response 1.
Clinical Recommendations
For your specific scenario (6 weeks post-Herceptin):
If the patient received PCV13/PCV15 before starting Herceptin: Consider waiting an additional 2 weeks to reach the 8-week minimum interval for immunocompromised patients 1.
If urgent protection is needed: PPSV23 at 6 weeks may still provide benefit, as studies show immunogenicity with intervals as short as 1 month, though responses may be suboptimal 1.
If the patient is vaccine-naïve: Prioritize PCV20 over PPSV23 for broader and more durable protection 4, 5.
Important Caveats
Antibody functionality (measured by opsonophagocytic activity) may be preserved even when IgG concentrations are lower in patients on immunosuppressive therapy 3.
Immune responses peak 4-6 weeks post-vaccination but may wane more rapidly in immunocompromised patients, with seroprotection decreasing significantly by 12 months 2.
No severe adverse events are typically associated with PPSV23 in cancer patients, and vaccination should not be withheld due to concerns about disease progression 1.
The most common adverse events include injection-site pain and swelling, which are generally mild to moderate 1, 7.