Seroprevalence of Antibodies against Diphtheria, Tetanus and Pertussis in Adult At-Risk Patients

Patients with chronic diseases are at increased risk of complications following infection. It remains, however, unknown to what extend they are protected against vaccine-preventable diseases. We assessed seroprevalence of antibodies against diphtheria, tetanus and pertussis to evaluate whether current vaccination programs in Belgium are adequate. Antibody titers were assessed with a bead-based multiplex assay in serum of 1052 adults with chronic diseases. We included patients with diabetes mellitus type 1 (DM1) (n = 172), DM2 (n = 77), chronic kidney disease (n = 130), chronic obstructive pulmonary disease (COPD) (n = 170), heart failure (n = 77), HIV (n = 196) and solid organ transplant (SOT) recipients (n = 230). Factors associated with seroprevalence were analysed with multiple logistic regression. We found seroprotective titers in 29% for diphtheria (>= 0.1 IU/mL), in 83% for tetanus (>= 0.1 IU/mL) and 22% had antibodies against pertussis (>= 5 IU/mL). Seroprotection rates were higher (p < 0.001) when vaccinated within the last ten years. Furthermore, diphtheria seroprotection decreased with age (p < 0.001). Tetanus seroprotection was less reached in women (p < 0.001) and older age groups (p < 0.001). For pertussis, women had more often a titer suggestive of a recent infection or vaccination (>= 100 IU/mL, p < 0.01). We conclude that except for tetanus, the vast majority of at-risk patients remains susceptible to vaccine-preventable diseases such as diphtheria and pertussis.

Automated summary

Patients with chronic diseases showed insufficient vaccine protection against diphtheria and pertussis, with factors like vaccination timing and age impacting the antibody levels. Tetanus, however, had higher protection rates among at-risk patients, especially when vaccinated within the last ten years.