Measles Titers in Long-Term Childhood Cancer Survivors

Purpose/Background: The number of long-term childhood cancer survivors (CCS) is increasing and is expected to exceed 500,000 by 2020. This population may be vulnerable to measles infection due to under-immunization or inadequate humoral immunity. We wish to determine if long-term CCS have evidence of humoral immunity to the measles virus. Studies suggest that up to 40% of CCS who are less than five years from the completion of therapy lack protective measles titers. Measles titers in long-term CCS who are greater than five years from the completion of chemotherapy have not been described. Methods/Approach: A retrospective chart review of CCS who attended one regional referral center from January 1, 2014 to December 31, 2018 identified CCS who measles titers assessed five or more years following the completion of treatment. Individuals with underlying immunodeficiency or who had received a bone marrow transplant were excluded. The presence or absence of measles titer, sex, age at diagnosis, age at therapy completion and age titers obtained were recorded. Results: Sixty-seven CCS who had measles titers assessed at least five years following the completion of therapy were identified. Of these individuals, 30 (40%) had a negative or equivocal titer to the measles virus. Conclusions: Our main finding was that only 55% of CCS had protective measles titers on average 11.4 years from the completion of therapy. In contrast, studies show that 91-95% of individuals maintain protective titers to the measles virus 20 years following two doses of measles vaccine. Further study should assess if CCS\u27s are an under-immunized population or are at risk for primary or secondary vaccine failure