Seroconversion following PPSV23 vaccination in children with type 1 diabetes mellitus.

Objective: To evaluate whether children with type 1 diabetes mellitus (T1DM) have optimal humoral immune response to pneumococcal polysaccharide vaccination (PPSV23) and to study factors affecting that response.

Methods: In this prospective pilot study, we recruited 29 children with T1DM who were vaccine naïve to PPSV23 and assessed serum-serotype specific IgG at baseline and 4-6 weeks post-immunization. We tested association between independent variables (age, gender, body mass index (BMI), hemoglobin A1c (HbA1c), glucose variability, and time in range assessed by continuous glucose monitors (CGM), insulin dose and outcome (log-2-fold change of immunoassay response between pre- and post-immunization testing) using linear regression.

Results: Eighty-eight percent of children (22/25) who completed the study had overall appropriate response with a median 4.2-fold change following immunization. When assessing PPSV23-exclusive serotypes, there was a statistically significant correlation between increasing age and greater response (0.16 log2-fold change per year, 95 % CI (0.014 to 0.3), p = 0.033). Higher BMI for age (p = 0.085) and a lower coefficient of glucose variation from CGM following immunization (p = 0.067) also coincided with greater vaccine response, with correlation statistically significant for certain pneumococcal serotypes for both.

Conclusions: Response to pneumococcal vaccination has not previously been assessed in children with T1DM, and our study demonstrates robust humoral immune response to PPSV23 vaccination in these children. Larger studies with a diverse representation and longer follow up to assess how humoral seroconversion correlates with clinical response to PPSV23 in this vulnerable population are warranted.