Knowledge of Vaccination History Does Not Predict Immune Status in Inflammatory Bowel Disease Patients

Abstract

Introduction: Current quality measures and management guideline in IBD emphasize vaccinations for vaccine-preventable illnesses, but do not specify assessment of current immune status. Given the recent resurgence of measles virus infections and separately, a Bordetella pertussis outbreak, we previously assessed the immune status of our IBD population (ACG 2015). We found that 13% of patients lacked detectable immunity to measles and 60% were non-immune to pertussis. In this follow up study, we obtained vaccination history from our patients and correlated it to their immune status. Methods: Patients involved in our previous immune status study were contacted in order to obtain their vaccination history. A simple five-question survey was administered via telephone. Knowledge of childhood vaccination and subsequent boosters was collected and compared to previously gathered immune status against measles and pertussis. Immunity was previously defined as: measles antibodies ≤0.8 Antibody index (AI)=negative immunity, 0.8-1.1 AI=equivocal immunity and titers ≥1.2 AI=positive immunity. For pertussis immunity, anti-pertussis (PT) antibodies ≤ 5 IU/mL were considered negative immunity. Simple statistical comparison was performed. Results: We were able to contact 88 of the original 122 patients. 62(70%) and 60 (68%) patients reported childhood vaccinations to measles and pertussis, respectively. 20 (23%) in both groups did not know their childhood vaccination history. 53 (85%) of those who recalled receiving the childhood vaccination for measles were also found to be immune; 18 (30%) of those who recalled receiving pertussis vaccinations were immune. All 6 patients who reported not receiving childhood measles vaccination had positive titers (without reporting a history of being infected with measles); 5 of 8 patients (62%) who reported not receiving the pertussis vaccination were immune. Analysis of booster vaccination recall did not change these results. See Tables 1 and 2.Table 1: IBD Patient Recall of Measles Vaccination Compared to their Actual Immune Status to Measles.Table 2: IBD Patient Recall of Pertussis Vaccination Compared to their Actual Immune Status to Pertussis.Conclusion: In this study, we found that IBD patient recall of vaccination history does not predict immune status. Given these findings, in combination with the known waning of immunity as patients age, we recommend obtaining titers in order to confirm immune status, and then vaccinating accordingly. Providing patients with documentation of their vaccination history and immune status would further improve this process.