Pneumococcal Booster Vaccination Is Necessary in Patients With Sickle Cell Disease

New research published by investigators in The Pediatric Infectious Disease Journal suggests that a pneumococcal booster vaccination could be necessary 5 years following the completion of a primary pneumococcal vaccination series in patients with sickle cell disease (SCD). This is due to a significant decline in seroprotection following the completion of a child’s pneumococcal vaccination series seen after the age of 5.¹

Parameters of the Study: Who Was Enrolled, What Was Studied, and How?

The retrospective, observational study investigated patients at Geneva University Hospitals in Switzerland. Patients with SCD diagnosed between 2009 and 2023 aged less than 16 years at diagnosis were eligible for analysis if pneumococcal vaccine serology results were available.¹

The investigators assessed antibodies to Streptococcus pneumoniae by examining serology tests for 3 representative serotypes contained in the pneumococcal 13-valent conjugate vaccine (Prevenar13; Pfizer)—14F, 19F, and 23F. If a patient harbored serotype-specific immunoglobulin G (IgG) levels over 0.30 mg/L in response to at least 2 of the 3 tested serotypes, they were considered seroprotected. Furthermore, to determine the role of a vaccine booster dose on seroprotection, patients were divided into 2 groups based on whether they had received a booster dose in addition to the primary vaccine series.¹

A total of 42 children with SCD between the ages of 0 and 19 years were followed between August 2007 and September 2023. Clinical characteristics of the cohort were reported; 56% had previously received a blood transfusion, 76% benefited from treatment with hydroxyurea, and 12% had a splenectomy. Eight patients did not have available vaccination records, leaving 32 children available for analysis.¹

Study Results: Pneumococcal Seroprotection Declines Following Primary Vaccination

Of the patients who had available records, all were fully vaccinated in accordance with their age. Across the population, 44% (15/34) received at least 1 booster dose at a median age of 3.47 years.¹

In the follow-up period, the 42 included patients had, on average, 3 pneumococcal vaccines at an average of every 1 or 2 years. Patients were an average age of 6 years at the time of their first pneumococcal serology. For 29% of the individuals with available immunization records, there was no immunity against pneumococcus recorded, despite having a documented up-to-date pneumococcal vaccination for their age group.¹

A Kaplan-Meier (KM) analysis demonstrated a dramatic loss of seroprotection beginning at the age of 5 years, starting from a high level of seroprotection. After a decade, most patients with SCD lost their seroprotection. The observation was applicable to the whole population, according to the investigators, because the KM curve for the entire cohort overlapped with that of the subgroup with vaccination records and the subgroup without vaccination records.¹

Following age-based analysis, seroprotection levels for individual serotypes were lower on average in children who had not yet received a booster vaccination compared with those who had. The authors cautioned that these observations are descriptive rather than statistically tested due to the small sample size.¹

The authors remarked upon the concerning observation that close to 20% of patients examined had no reliable vaccination history available. They wrote that a more centralized and organized method to document vaccination history could be warranted to improve recordkeeping and ensure continuity of care, especially for patients who utilize multiple providers.¹

Booster doses were found to be especially important in keeping seroprotection levels high. Research demonstrates that many patients with SCD who receive a pneumococcal vaccination often remain at a heightened risk of serious complications if infected due to comorbidities and their immunocompromised state. A booster dose at the 5-year mark post-vaccination could be a necessary component of prevention for patients with SCD, especially for those with a history of transfusions or allogeneic stem cell transplantation.^1,2

REFERENCES

1. Noble C, Gualtieri R, Mattiello V, et al. Vaccine immunity against pneumococcus in children with sickle cell disease: A retrospective single-center study. Ped Infect Dis J. 2025. doi:10.1097/INF.0000000000004947

2. Halpern L. Children with sickle cell disease have higher rates of invasive pneumococcal disease despite vaccination. Pharmacy Times. Published May 14, 2025. Accessed December 5, 2025. https://www.pharmacytimes.com/view/children-with-sickle-cell-disease-have-higher-rates-of-invasive-pneumococcal-disease-despite-vaccination