Different Response Patterns to Inactivated, Subunit or Live Attenuated Vaccines in Children after Treatment for Malignancies and Bone Marrow Transplantation

Objective: In pediatric patients treated for malignancies with chemotherapy or bone marrow transplantation (BMT), the disease and the treatment lead to impaired immunity and loss of immunity continues for a time period after the completion of therapy. Therefore, revaccination of these children is necessary. The aim of this study was to examine the differences between different treatment groups, namely solid tumors, leukemias and BMT patients, for their response to inactivated or subunit or live attenuated vaccines at least 6 months after the cessation of the of treatment. Materials and Method: The study was performed prospectivly in 35 patients with solid tumors (Group I), 32 patients with leukemia (28 ALL, 4 AML) (Group II) and 13 patients after BMT (Group III). Inactivated (Diphtheria, tetanus), subunit (acellular pertussis, hepatitis B, hepatitis A) and live attenuated (measles-mumps-rubella (MMR), varicella) vaccines were applied to patients. Blood samples taken from the all patients before vaccination and 1 month after vaccination. IgG antibodies against measles-mumps-rubella and varicella were evaluated in vitro. Results: For inactivated vaccines, the level of anti diphteria antigen was highly positive in Group I and II, 80% and 71.8% respectively, but only 53.8% of Group III patients were positive before vaccination. After one dose all of these levels became 100%. For tetanus it was the same pattern (84.4% 88.6% and 46.2%, low in Group III). They all reached 100% after vaccination with one dose. Anti pertussis IgGs were low in all 3 groups, 54.3%, 46.9%, 38.5% respectively. These levels were 66.7%, 66.7%, 50% after the vaccination and the differences were meaningful for Groups I and II (p : 0.02 and 0.002), but not for Group III (p : 0.068). In subunit (purified antigen) vaccines, for Hapatitis B, Anti HBs levels were low in all groups (60%, 37.5%, 46.2%) before vaccination. After one dose, 55.6%, 64.3%, 50% became positive, but only after the second dosage 100% of the patients were positive. For Hepatitis A, positive levels of antiHAV IgG before vaccination were 28.6%, 37.5%, 53.8% for the 3 groups. Except for one patient in the BMT group 100% became positive with one dose. Among live, attenuated viruses, measles, rubella, mumps vaccinations were applied. Anti-rubeola IgG levels were positive in 45.7%, 34.4% 15.4% of patients in 3 groups before vaccination. After one dose they all became positive except for one patient in each group, who responded after one more dose. For rubella, 85.7%, 78.1% and 61.5% of patients were positive for anti-rubella IgG before vaccination in respective groups and they all became 100% positive after one dose. Before mumps vaccination, 82.9%, 71.9% and 46.2% of patients were positive for anti-mumps IgG before first dose. 83.3%, 100% and 50% became also positive after one dose, but after the second dosage 100% were positive. 65.7%, 59.4% and 53.8% of the patients were seropositive for antiVZV IgG respectively before vaccination. Except for four cases in Group I, the rest achieved seropositivity after one dose. Conclusion: In our study, after one booster dose of vaccine, all patients had very good antibody response against to diphtheria, tetanus, hepatitis A, rubella vaccines at least 6 months after the cessation of therapy for leukemia and solid tumors and 12 months after BMT. Protection after mumps vaccine was in moderate levels in leukemia and solid tumor groups, but not in BMT group. All groups responded moderately for measles, varicella, pertussis, hepatitis B, some needing one more booster. BMT group seems to be the maximum looser and the least responder after vaccination. The groups showed differences in antibody responses to vaccines, according to age, the time passed after the cessation of treatment and their primary vaccination status. To evaluate the response obtained, following antibody levels for response to vaccination is necessary and a booster should be considered when there is a decrease or loss in these levels.