Pediatric Infectious Diseases Program for Immunocompromised Hosts

Splenectomy Vaccine Protocol for Pediatric Solid Organ Transplant Patients

Rationale:

The spleen functions to clear bacteria from the blood as well as lymphoid tissue where encapsulated bacteria are introduced to B cells and production of new antibodies is initiated. Thus, asplenic patients are at particular risk for infections due to encapsulated organisms including:

 Streptococcus pneumonia 57%  Haemophilus influenza 22%  Neisseria meningitis

Asplenic individuals are also at increased severity to some parasitic infections given that the spleen removes infected erythrocytes including

 Babesia  Malaria (particularly primary infection)

Possibility of increased disease due to ehrlichia and CMV?

Time frame:  The ideal time from vaccines to transplant is dependent on the vaccine status of the candidate but in general all vaccines should be finished 2 weeks before surgery to allow for appropriate immunity and usually at least 10 weeks is needed.  If pre-splenectomy vaccines are not possible then the vaccines should be given >2 weeks postop except when there is immunosuppression then vaccines should be delayed until 3 months post-op which is typically when the period of intense immunosuppression is over.

Pneumococcal vaccine — Two pneumococcal vaccines are available for use in the United States:  The 23-valent pneumococcal polysaccharide vaccine (PPSV23) contains capsular polysaccharides from 23 common serotypes of S. pneumoniae. This vaccine is for use in children > 2 years of age and does not produce memory responses so needs to be repeated every 5 years  A 13-valent conjugate pneumococcal vaccine (PCV13) protects against 13 capsular serotypes which are known to cause 90% of invasive disease in children and is more effective than PPSV23 in children younger than two years and has comparable or enhanced immunogenicity compared with PPSV23 in adults. The conjugate vaccine produces memory responses by eliciting T cell immunity.

Pediatric Infectious Diseases Program for Immunocompromised Hosts

Pneumococcal disease susceptibility is lifelong but with higher incidences at the extremes of age <2 years and > 65years

In general, all children should receive the routine PCV13 series with doses at 2,4,6 and 12-15 mo. If this series is not finished before splenectomy is considered then as many doses to get to 4 as possible should be administered at 4 week intervals followed in 8 weeks after the last dose with PPSV23 in children > 2years of age (Table 1).

Table 1. Pneumococcal Vaccine

Pneumococcal Vaccine Status Vaccines before Splenectomy Booster after Splenectomy Child with 4 doses PCV13* If > 2yrs PPSV23 8 weeks PPSV23 every 5 years after last PCV dose Child with 1-3 doses PCV13 and if > 2yrs followed PPSV23 every 5 years PCV13** by PPSV23 8 weeks after last (the least number of effective PCV dose doses is usually 2 Child with 0 doses of 2 doses of PCV13 8 weeks PPSV23 every 5 years PCV13** apart and if > 2yrs followed by PPSV23 8 weeks after last PCV dose * If the PCV administered was PCV7 then a dose of PCV13 is warranted before the PPSV23 **some sources state that children > 6 years of age can receive one dose of PCV13 and not the two priming doses, but we prefer 2 for transplant candidates if time allows

Haemophilus influenzae vaccine — Haemophilus influenzae type b (Hib) conjugate vaccine. Causes memory responses by eliciting T cell immunity and is part of the routine childhood series

Most individuals are immune even if unimmunized by 6 years of age.

Table 2. Haemophilus influenzae vaccine HIB Vaccine Status Vaccines before Splenectomy Booster after Splenectomy Child with 2-4 doses* 1 dose none Child with 0-1 doses < 5 years 2 doses 8 weeks none apart > 5 year 1 dose *some sources state that children > 5 with any previous doses and children <5 who are fully immunized would not require an additional dose, but we feel all transplant candidates should have a booster before splenectomy

Pediatric Infectious Diseases Program for Immunocompromised Hosts

Meningococcal Vaccine.

Three meningococcal vaccines are available for use in the United States. None cover the serogroup B, which is a major type in infant disease.

The disease is biphasic with the highest incidence in young infants and a second peak in college age people.

 The quadrivalent meningococcal conjugate vaccines are Menactra (MenACWY-D) and Menveo (MenACWY-CRM). These vaccines cause immunologic memory. Menactra should not be given with the primary series of pneumococcus or between the ages of 9-23 months when pneumoccous is also being given.  The quadrivalent meningococcal polysaccharide vaccine is Menomune (MPSV4) and does not induce memory.

Table 3. Meningococcal Vaccine Vaccine Status Vaccines before Splenectomy Booster after Splenectomy Child <2 years two doses of Menveo, three Menactra or Menveo after 3 months apart second dose after years then every 5 years 12 mo Child >2 years two doses of Menveo or Menactra or Menveo after 3 menactra 2 months apart years then every 5 years