Question explored with the scientific record
should asplenics be vaccinated against Covid and influenza?
The short version: the evidence here does not directly answer whether asplenics should get COVID or flu shots, and what exists shows their immune response is often blunted.
The retrieved studies mostly cover pneumococcal and meningococcal vaccines in asplenic patients, not COVID or influenza. One 2021 meta-analysis found only about half of asplenic patients get flu shots at all, and coverage for other vaccines ranges from 13% to 55% [2]. That tells you the system itself is not confident enough to get these patients vaccinated consistently. The 2004 meningococcal study is more telling: asplenic adults mounted protective responses in 75% of cases after one dose, but their antibody levels were about 9 times lower than healthy controls [9]. A 1979 study of Hodgkin's patients who had their spleens removed showed some failed to reach protective antibody levels after pneumococcal vaccination [8]. If the spleen is central to mounting a strong response, and these patients respond weakly, that is a real question about whether the shots work for them at all.
For COVID specifically, none of these records test asplenic patients. The Korean pneumococcal surveillance study mentions only 2 asplenic children out of 188 cases [1]. That is not evidence about COVID vaccines. The Italian RSV study lists asplenia in 0.7% of its cohort but says nothing about outcomes [3]. The burden of proof sits with anyone claiming these vaccines protect asplenic people. The evidence here does not meet it.
My call: the evidence is not clear for either COVID or flu in asplenics. What exists shows weaker immune responses, and no study here measures real outcomes like hospitalization or death in this group. Confidence: low.
Sources used 5
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Hospital-Based Surveillance of Pediatric Invasive Pneumococcal Diseases, 2016–2023 in Korea: Serotype Trends and Vaccination Policy
Hospital-based surveillance of pediatric invasive pneumococcal disease (IPD) in Korea from 2016 to 2023 shows a COVID-19–associated dip in IPD, followed by serotype shifts with a large portion of burden falling to PCV20-covered or related serotypes, informing vaccination policy …
DOI: 10.3346/jkms.2025.40.e250 -
Immunization coverage among asplenic patients and strategies to increase vaccination compliance: a systematic review and meta-analysis
This study systematically reviews and meta-analyzes vaccination coverage among asplenic/splenectomized patients and evaluates strategies to improve vaccine adherence, finding generally suboptimal coverage across vaccines and showing that hospital-based protocols and enhanced hea…
DOI: 10.1080/14760584.2021.1886085 -
Characteristics of the First Italian Older Adults Vaccinated with an Adjuvanted Respiratory Syncytial Virus (RSV) Vaccine
This cross-sectional study characterizes the first cohort of Italian older adults vaccinated with the adjuvanted RSVPreF3 OA vaccine in Liguria (n=453), detailing their sociodemographic and clinical characteristics, high prevalence of comorbidities, uptake of other vaccines, and…
DOI: 10.3390/medicina61010067 -
Response of Patients with Hodgkin's Disease to Pneumococcal Vaccine
In postsplenectomized patients treated for Hodgkin's disease, pneumococcal vaccination induced significantly lower serotype-specific antibody responses than normal controls, with responses improving over time after therapy and some patients failing to mount protective levels or …
DOI: 10.7326/0003-4819-90-6-887 -
Immune Response to Meningococcal Serogroup C Conjugate Vaccine in Asplenic Individuals
This study assesses the immunogenicity of meningococcal serogroup C–conjugate vaccine in asplenic adults by measuring serum bactericidal activity and serogroup C–specific IgG before and after vaccination, examining how factors such as reason for splenectomy and time since splene…
DOI: 10.1128/iai.72.1.332-337.2004