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Active immunization of children with leukemia and other malignancies
1Division of Pediatric Hematology and Oncology, Oregon Health Sciences University, Portland.
Insights
Pediatric cancer patients may lose immunity and respond poorly to vaccines, especially live ones. Tetanus and diphtheria vaccines are generally safe and effective, but others like pneumococcus may be less so during chemotherapy.
Area of Science:
- Pediatric Oncology
- Immunology
- Vaccinology
Background:
- Healthy children develop long-lasting immunity from routine vaccinations.
- Cancer patients undergoing immunosuppressive therapy may experience waning immunity and reduced vaccine responsiveness.
- The safety and efficacy of vaccines in this vulnerable population require careful consideration.
Purpose of the Study:
- To review existing evidence on vaccine-induced immunity and responsiveness in pediatric cancer patients.
- To assess the safety of various vaccine types in this population.
- To identify specific vaccines that may be compromised during or after antineoplastic therapy.
Main Methods:
- Review of published evidence regarding vaccine response and safety in children undergoing cancer treatment.
- Analysis of antibody titers and immune protection following vaccination.
- Comparison of vaccine responses between healthy children and those receiving immunosuppressive therapy.
Main Results:
- Tetanus, diphtheria, and polio vaccine-induced antibody titers are generally preserved.
- Immunity to varicella, influenza, and hepatitis B (natural) is compromised during therapy.
- Responsiveness to vaccines like Haemophilus influenza B, influenza, pneumococcus, and hepatitis B is diminished, particularly in leukemia patients during chemotherapy.
Conclusions:
- Toxoids and inactivated vaccines are generally safe for pediatric cancer patients.
- Live attenuated vaccines pose risks and require careful benefit-risk assessment.
- Vaccine responsiveness is significantly reduced during chemotherapy, necessitating tailored immunization strategies.
Abstract:
Active immunization against measles, Haemophilus influenza B, tetanus, diphtheria, hepatitis B, influenza, poliomyelitis, and, when indicated varicella and pneumococcus induces long-lasting immunologic protection in most healthy pediatric vaccine recipients. Among children receiving immunosuppressive therapy for cancer, possible early loss of specific immunity acquired from prior vaccination or disease, and likely diminished responsiveness to initial or booster vaccination must be considered. In addition, the safety of vaccine administration requires separate study in this population. Published evidence demonstrates preservation of vaccine-induced antibody titers against tetanus, diphtheria, poliomyelitis and (in children treated for lymphoma) pneumococcus. In contrast, prior immunity to varicella, influenza, and hepatitis B (when naturally acquired), and measles (acquired by vaccination) is compromised during and/or after antineoplastic therapy. Studies of immunologic protection acquired by prior vaccination against hepatitis B, varicella, and H influenza have not been published. The safety of administering toxoids and inactivated vaccines in this population is well documented. In contrast, morbidity must be expected if live attenuated vaccines (oral polio vaccine, attenuated measles vaccine or attenuated varicella vaccine) are administered to children receiving anti-cancer therapy. The risks of using live vaccines should be measured against demonstrable benefits in any vaccine program. The response to initial or booster immunizations against tetanus and diphtheria are similar to those in healthy children. For all other immunizations reviewed, responsiveness is diminished during periods of chemotherapy, more strikingly in children treated for leukemia than for solid tumors. Antibody responses to these vaccines range from slightly blunted (in the case of H influenza B) to marginal (influenza) or completely useless (pneumococcus and hepatitis B in children treated for leukemia).