Abstract
‹Background› Live vaccines are descreibed as contraindications in the package inserts of immunosuppressive agents in Japan because of the risk of viral infection by vaccine strain. However, viral infections such as measles and chickenpox are associated with serious complications in immunocompromised children, and can sometimes be fatal. So, using live vaccines for patients receiving immunosuppressants is not prohibited in the immunization guideline in Japan and this issue has been controversial. We initiated immunization with attenuated live vaccines in children receiving immunosuppressants.
‹Patients and Methods› Patients receiving immunosuppressants (calcineurin inhibitors, purine synthesis inhibitors, or both of them) that showed negative or borderline antibody titers of IgG against the viruses that cause measles, rubella, chickenpox and mumps were included in the study. We immunized these individuals with attenuated live vaccines while underlying disease activities were stable, and after obtaining informed consent. Antibody titers against the viruses and adverse events were monitored.
‹Results› A total of 55 immunizations were performed in 40 patients (28 males and 12 females). The study subjects consisted of patients with nephrotic syndrome (31), renal transplant (7), and collagen disease (2). The median age at vaccination was 10 years (range 1-24-years old). Patients were receiving calcineurin inhibitors (cyclosporine or tacrolimus; n=24), purine synthesis inhibitors (mizoribine, mycophenolate mofetil or azathioprine; n=13) or both (n=18). Thirteen patients (24%) were also treated with a low dose of steroids. Measles-rubella (MR) vaccines were administered to 22 patients, varicella vaccines to 18 and a mumps vaccine to 15 individuals. The overall seroconversion rate was 65% (measles 90%, rubella 93%, varicella 44% and mumps 43%). Four patients (7%) showed mild adverse events (transient fever in 2, transient rash in 1, and relapse of nephritic syndrome in 1) but no serious adverse events were seen.
‹Conclusion› Immunization with attenuated live vaccines was effective and safe in children receiving immunosuppressants. More clinical data need to be collected to further evaluate their safety.
