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Published on: March 14, 2011
Randomized study of early versus late immunization with pneumococcal conjugate vaccine after allogeneic stem cell
Catherine Cordonnier1, Myriam Labopin, Virginie Chesnel
1Hematology Department, Henri Mondor Teaching Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP) and Paris 12 University, Créteil, France. carlcord@club-internet.fr
Insights
Starting the 7-valent pneumococcal conjugate vaccine (PCV7) series at 3 months after stem cell transplantation is as effective as starting at 9 months. Early vaccination provides timely protection against invasive pneumococcal disease.
Area of Science:
- Immunology
- Transplantation Medicine
- Vaccinology
Background:
- Invasive pneumococcal disease (IPD) is a serious risk post-allogeneic stem cell transplantation (SCT), with high incidence within the first year.
- The 23-valent pneumococcal polysaccharide vaccine (PPV23) shows limited efficacy in SCT recipients, particularly early post-transplant.
- Optimal timing for conjugate pneumococcal vaccines, like the 7-valent pneumococcal conjugate vaccine (PCV7), remains undefined.
Purpose of the Study:
- To determine if initiating the PCV7 vaccination series 3 months post-SCT is non-inferior to initiating it at 9 months post-SCT.
- To evaluate the immune response to early versus delayed PCV7 vaccination in allogeneic SCT recipients.
Main Methods:
- A multicenter, randomized, noninferiority trial involving 158 patients undergoing myeloablative SCT.
- Participants received 3 doses of PCV7 one month apart, starting either at 3 months (early) or 9 months (late) post-transplant.
- The primary endpoint was the response rate (antibody level ≥ 0.15 μg/mL for all 7 serotypes) one month after the third PCV7 dose, with a noninferiority margin of 20%.
Main Results:
- The response rate in the early vaccination group (3 months) was 79% (45/57 patients).
- The response rate in the late vaccination group (9 months) was 82% (47/57 patients).
- The difference in response rates was not statistically significant, meeting the noninferiority criterion.
Conclusions:
- PCV7 vaccination initiated at 3 months post-SCT is not inferior to vaccination initiated at 9 months post-SCT.
- Early vaccination (3 months) is recommended to provide prompt protection against *Streptococcus pneumoniae* due to the risk of early-onset IPD.
- Consideration should be given to potentially shorter-lasting responses and less efficient priming for PPV23 boost with early vaccination.
Background:
Invasive pneumococcal disease is a life-threatening complication after allogeneic stem cell transplantation, and at least 20% of cases occur within 1 year after transplantation. The 23-valent pneumococcal polysaccharide vaccine (PPV23) has limited efficacy, especially during the first year after transplantation. The immune response to the conjugated vaccines is expected to be better than that to the polysaccharide vaccine, but the optimal timing of vaccination is not defined. Our objective was to show that a 7-valent pneumococcal conjugate vaccine (PCV7; Prevnar) was not inferior when first given 3 months after transplantation, compared with when first given 9 months after transplantation.
Methods:
We performed a multicenter, randomized, noninferiority study involving 158 patients from 13 European Group for Blood and Marrow Transplantation centers who were randomly allocated at approximately 100 days after myeloablative stem cell transplantation to receive a series of vaccinations (3 doses of PCV7 given 1 month apart) that was started immediately (i.e., 3 months after transplantation) or 6 months later (i.e., 9 months after transplantation). The primary evaluation criterion was the rate of response (antibody level, > or = 0.15 microg/mL for each of the 7 serotypes) at 1 month after the third dose of PCV7. The noninferiority margin was 20%. All patients were followed up for 24 months after transplantation or until death, whichever occurred first.
Results:
We found that the response rate was not lower after early vaccination (79% [45 of 57 patients]) than after late vaccination (82% [47 of 57 patients]) (difference, -3.5%; 90% confidence interval, -15.6 to 8.6; not significant).
Conclusions:
We conclude that PCV7 vaccination at 3 months after stem cell transplantation is not inferior to PCV7 vaccination at 9 months after transplantation. Because invasive pneumococcal disease can occur early, we recommend starting the PCV7 vaccination series at 3 months after transplantation to ensure earlier protection against Streptococcus pneumoniae. However, the early vaccination may result in only short-lasting response and may not prime for a 23-valent pneumococcal polysaccharide vaccine boost as efficiently as the late vaccination.
