Vaccination Following Leukemia Treatment: Viral Vaccine Responses in Survivors of Acute Lymphoblastic Leukemia.

Background: Emerging treatment strategies have enhanced life expectancy for cancer patients, but late complications, including vaccine-preventable infections from diminished antibody titers, are common. This study evaluates viral vaccine immunity in children post-leukemia treatment and examines the need for additional vaccine doses and their effectiveness.

Methods: Our cohort included 62 children diagnosed with acute leukemia. We recorded patients' sex, age at diagnosis, type of leukemia, risk groups, vaccination status prior to chemotherapy, and serology results for hepatitis A, hepatitis B, varicella, measles, rubella, and mumps (MMR) both at the end of chemotherapy and after vaccination following chemotherapy.

Results: Post-treatment, patients exhibited a loss of protective antibody responses: hepatitis A (44.4%), hepatitis B (67.7%), varicella (62.5%), measles (46.9%), rubella (43.5%), and mumps (50%). Notably, high-risk group acute lymphoblastic leukemia (HRG ALL) patients had a marked decrease in protective antibodies for hepatitis B, measles, rubella, and mumps compared to standard/intermediate risk group (SRG/IRG) ALL patients (p<0.05). Among the seronegative patients, following vaccination, five (15.2%) remained seronegative for varicella, one (2.2%) for hepatitis A, one (3.5%) for measles, one (3.8%) for rubella, and two (6.5%) for mumps.

Conclusion: Our study highlights a significant loss of vaccine-protective antibody responses after acute leukemia treatment, particularly among HRG. The increased vulnerability to vaccine-preventable infections, particularly hepatitis B, measles, rubella, mumps, and varicella, in HRG ALL patients highlights the importance of ongoing monitoring of immunization status and potential revaccination strategies to ensure adequate protection against infectious diseases.