P2.N263: We Gave it a Shot: Streptococcus Pneumoniae Meningitis in a Fully Vaccinated Adolescent

Introduction: According to the Center for Disease Control, the introduction of the pneumococcal conjugate vaccine (PCV) has reduced invasive pneumococcal disease by 99%. However, completion of the vaccine series does not confer complete protection, and breakthrough infections occur sporadically. We discuss a completely immunized adolescent with Streptococcus pneumoniae serotype 19F meningitis, a serotype covered in PCV.

Case Description: A previously healthy 12-year-old male presented to the emergency department with one week of fever (Tmax 102F), generalized weakness, vomiting, and headache. He was fully vaccinated, including a completed PCV13 series. He was afebrile and hemodynamically stable but appeared ill and somnolent with neck stiffness on exam. Labs showed 22.6 WBCs (90% neutrophils). Cerebrospinal fluid (CSF) showed glucose of 6 mg/dl, protein of 114 mg/dl, 80 RBCs, and 1220 WBCs (11% neutrophils, 84% lymphocytes). CSF gram stain had many WBCs and rare gram-positive cocci in pairs. Within four hours of collection, CSF PCR was reported positive for S. pneumoniae. He received vancomycin, cefepime, and dexamethasone, and was admitted. CSF subsequently grew S. pneumoniae more than thirty-one hours after PCR identification.

Initial CT brain and neck revealed pansinusitis and mastoiditis. He underwent frontal sinusotomy, ethmoidectomy, maxillary and sphenoid antrostomy, and septoplasty. Sinus cultures were polymicrobial. Per infectious disease recommendations, he started a 4-week course of vancomycin, ceftriaxone, and metronidazole. Brain MRI showed a left temporal extra-axial abscess and bilateral frontal non-enhancing restricted diffusion.

Repeat brain MRI visualized a 0.6 cm rim-enhancing collection near the frontal lobe concerning for subdural empyema with increased leptomeningeal enhancement and possible evolving embolic infarcts. Surgical intervention was not necessary. On hospital day 11, his neurological status returned to baseline. Serotyping showed the S. pneumoniae to be 19F, contained in PCV13 (Figure 1). Immunology was consulted for immunodeficiency workup, which showed normal IgG, IgM, IgA, and complement levels, and normal diphtheria, tetanus, and pneumococcal serology. Final brain MRI revealed improved leptomeningeal enhancement and left temporal extra-axial collection. He completed antibiotics and was discharged home with immunology follow-up.

Discussion: Despite receiving the entire PCV13 series and having serological correlate of vaccine protection (Figure 1), our patient developed 19F S. pneumoniae meningitis. It may not be sufficient to gauge vaccine protection solely by quantitation of serologies but also by considering antibody avidity and opsonophagocytic activity. One study showed a sub-variant within a pneumococcal serotype that was associated with breakthrough infections. Our patient presented older, less acutely, with a less reported infection site and serotype than typically seen in the literature. This case serves as a lesson that, though rare, PCV immunization does not confer complete protection from invasive vaccine-serotype pneumococcal infection.

Conclusion: Although immunization has extensively decreased the incidence of invasive S. pneumoniae disease, it is prudent to consider vaccine-covered organisms in the diagnostic workup.