Immunodeficiency in Children With Invasive Pneumococcal Disease.

Invasive pneumococcal disease (IPD) continues to be a significant contributor to childhood morbidity and mortality. Such occurrences persist despite global vaccination initiatives. Previously unrecognized immunodeficiencies are highlighted due to the presence of IPD in otherwise healthy children. This narrative review has examined the immunologic mechanisms by synthesizing evidence from multicenter studies. These immunologic mechanisms predispose children to IPD. The most common defects of the immune system include antibody and complement deficiencies, congenital asplenia, or innate immune signaling disorders involving MYD88 and IRAK4. Even though pneumococcal conjugate vaccines have played their role in drastically reducing the disease burden, the occurrence of breakthrough infections continues. This happens due to non-vaccine serotypes and impaired immune responses. Early identification of underlying immune defects can be achieved through a structured postinfection evaluation. Recognizing IPD as a potential indicator of immunodeficiency allows clinicians to individualize management. This is achieved through optimization of vaccines, antibiotic prophylaxis, and long-term follow-up. Thereby, the outcome is decreased recurrence and advancing equitable prevention of severe pneumococcal disease in children.