Efficacy, immunogenicity, and evidence for best-timing of pneumococcal vaccination in splenectomized adults: a systematic review

ABSTRACT

Introduction

Streptococcus pneumoniae is the most frequent cause of overwhelming post-splenectomy infections. Pneumococcal vaccination is generally recommended for splenectomized individuals. However, most of our knowledge comes from a few observational studies or small randomized clinical trials. We conducted this systematic review to assess the evidence of efficacy, antibody response, and the best timing for pneumococcal vaccination in splenectomized individuals.

Areas covered

The systematic review was conducted according to the PRISMA guidelines. We screened 489 articles, included 21 articles, and assessed the risk of bias using Cochrane RoB 2 and ROBINS-I. We summarized the findings narratively due to the heterogeneity of the studies.

Expert opinion

Splenectomized individuals seem to have adequate antibody responses to pneumococcal vaccines. No differences in antibody responses were observed compared to healthy controls, except in one study. The studies were heterogeneous, and the majority had moderate to high degree of bias. There is a lack of clinical evidence for efficacy and best timing of pneumococcal vaccination in splenectomized individuals. Randomized clinical trials addressing these issues are needed.

KEYWORDS:

• Streptococcus pneumoniae
• pneumococcus
• pneumococcal vaccination
• 23-valent pneumococcal polysaccharide vaccine
• pneumococcal conjugate vaccine
• splenectomy
• adults

Author contributions

E Lenzing, O Rezahosseini, SK Burgdorf, SD Nielsen, and ZB Harboe contributed substantially to the conception and design of the study and interpretation of the relevant literature. E Lenzing and O Rezahosseini did the search. E Lenzing, O Rezahosseini, and ZB Harboe screened papers, determined the risk of bias, and extracted data. E Lenzing, O Rezahosseini, and ZB Harboe wrote the first draft of the manuscript. SK Burgdorf and SD Nielsen commented and revised the manuscript. All authors read and approved the final version of the manuscript.

Declaration of interest

O Rezahosseini has received a grant from The Research Foundation of Rigshospitalet; SDN has received unrestricted research grants from Novo Nordisk Foundation and Independent Research Fund (FSS); ZB Harboe has received a grant from Independent Research Fund Denmark for studying ‘vaccine-preventable diseases in immunocompromised adults’ (grant no. 134-00257B). The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

ZB Harboe has received a grant from Independent Research Fund Denmark for studying ‘Vaccine-preventable diseases in immunocompromised adults’ (grant no. 134-00257B).