Addressing functional asplenia in sickle cell disease: A quality improvement approach to improve vaccination rates

Abstract

Abstract Background: Vaso-occlusion in sickle cell disease (SCD) leads to functional asplenia, increasing severe infection risk from encapsulated bacteria, viruses, and parasites (Scourfield et al., 2025). Patients with SCD also face systemic barriers, particularly decreased access to treatment (Khan et al., 2022). Our hematology sickle cell clinic identified suboptimal vaccine adherence: pneumococcal at 35%, meningococcal ACWY (MenACWY) at 15%, meningococcal B (MenB) at 20%, Haemophilus influenzae type b (H. flu) at 48%, and influenza at 39% in 41 adult patients with SCD seen from 2022-2024. AIM Statement: Our goal was to increase adherence rates to CDC-recommended asplenia-related vaccines (pneumococcal, MenACWY + B, H. flu, and influenza) by 50% at 9 months and 75% at 12 months, beginning April 2025. Methods: Root causes of care gaps were mapped in a fishbone diagram. Examples included provider difficulty in assessing vaccine status from electronic medical record (EMR) reconciliation issues, provider time constraints, limited patient knowledge, insurance coverage, and the absence of a vaccine administration protocol. An interdisciplinary team of providers, a nurse care manager (NCM), pharmacists, and IT personnel implemented a workflow for vaccine review, administration, and patient education. Key high impact interventions included: (1) addition of functional asplenia to active problem lists to flag vaccine-eligible patients and improve accurate coding and billing; (2) a structured pre-visit workflow where NCM reviewed vaccination gaps and documented recommendations for providers; (3) development of an EMR vaccine order set in collaboration with pharmacy; and (4) creation of patient education materials accompanied by NCM-led counseling. We evaluated interim outcomes through chart review at three months (April-July 2025) using a PDSA cycle framework. Results: At three months post-intervention, 36 patients were seen in clinic. NCM pre-visit review identified 94.4% (n=34) patients requiring an updated vaccine or booster. Education was provided to 58.3% (n=21) of patients during the visit, with 50% (n=18) agreeing to or requesting vaccination. Providers prescribed vaccines for 52.7% (n=19) of eligible patients. A key barrier encountered was the inability to run insurance prior authorizations (PAs) for in-clinic vaccination, prompting a shift to pharmacy-based prescribing and administration where patients access their medications. Preliminary post-intervention updated vaccination rates increased to 41.7% for pneumococcal, 27.8% for MenACWY, and 77.8% for H. flu, representing promising early gains which will be further updated. Men B rate was 11.1% as other vaccines were prioritized in the initial phase per CDC. Conclusions/Implications: We identified a significant care gap in vaccination adherence for adults with SCD. We demonstrated the potential of NCM and pharmacy-led workflow integrated with EMR tools to address adherence gaps. However, systemic barriers (e.g., PA for in clinic administration) require further addressing. Continued PDSA cycles are underway to reach our goals. This intervention model may be generalizable to other populations with asplenia in benign hematologic conditions.