Influenza vaccine effectiveness and disease burden in children and adolescents with sickle cell disease: 2012‐2017

Abstract

Background Data are limited on the burden of influenza and seasonal influenza vaccine effectiveness (VE) in children with sickle cell disease (SCD). Methods We used a prospectively collected clinical registry of SCD patients 6 months to 21 years of age to determine the influenza cases per 100 patient‐years, vaccination rates, and a test‐negative case‐control study design to estimate influenza VE against medically attended laboratory‐confirmed influenza infection. Influenza‐positive cases were randomly matched to test‐negative controls on age and influenza season in 1:1 ratio. We used adjusted logistic regression models to compare odds ratio (OR) of vaccination in cases to controls. We calculated VE as [100% × (1 − adjusted OR)] and computed 95% confidence intervals (CIs) around the estimate. Results There were 1037 children with SCD who were tested for influenza, 307 children (29.6%) had at least one influenza infection (338 infections, incidence rate 3.7 per 100 person‐years; 95% CI, 3.4‐4.1) and 56.2% of those tested received annual influenza vaccine. Overall VE pooled over five seasons was 22.3% (95% CI, −7.3% to 43.7%). Adjusted VE estimates ranged from 39.7% (95% CI, −70.1% to 78.6%) in 2015/2016 to −5.9% (95% CI, −88.4% to 40.4%) in the 2016/17 seasons. Influenza VE varied by age and was highest in children 1‐5 years of age (66.6%; 95% CI, 30.3‐84.0). Adjusted VE against acute chest syndrome during influenza infection was 39.4% (95% CI, −113.0 to 82.8%). Conclusions Influenza VE in patients with SCD varies by season and age. Multicenter prospective studies are needed to better establish and monitor influenza VE among children with SCD.

Influenza Vaccination Receipt in Pediatric Patients With Cancer or Sickle Cell Disease

“…Conversely, patients with SCD had significantly higher rates of influenza vaccination than the state and nation, which remained true when compared with the United States’ general population of Black or African American children 18. Our findings are similar to the IIV receipt rates found in other states’ pediatric cohorts with cancer or SCD, suggesting similar receipt among these pediatric populations across states with different degrees of IIV receipt 9–13…”

“…The Advisory Committee on Immunization Practices recommends annual inactivated influenza vaccination (IIV) for all immunocompromised individuals 8. Historically, IIV receipt has been poor in both SCD and pediatric cancer populations, ranging from 20% to 60% in SCD, 40 to 50% in solid and central nervous system (CNS) tumors, and 60% to 70% in hematologic malignancies 9–13. Quality improvement studies have shown the efficacy of outpatient interventions 12–16.…”

Maintenance of a High Influenza Vaccination Rate and Improvement in Health Outcomes in a Pediatric Sickle Cell Disease Clinic

“…Patients with influenza were significantly younger than those without influenza (4.67 vs. 10.03 y, P = 0.005, Table 1). The influenza vaccination rate for pediatric patients with SCD at BMC was higher than the vaccination rates in previous studies outside of BMC, 7,[21][22][23][24][25][26] while the IRH rate 10,13,27,28 and the influenza-positive rate, 25,29,30 for the pediatric patients with SCD were lower than the previous rates in the literature (Table 4).…”

Influenza vaccination rates and hospitalizations among Medicaid enrollees with and without sickle cell disease, 2009–2015

“…45 One singlecenter study indicated vaccine effectiveness among children with SCD ranged between −6% and 40%. 46…”

“…Furthermore, serologic response among persons with SCD may wane more rapidly over time, 20 and the magnitude and duration of response may be affected by use of chronic transfusion therapy 21,44 and splenic function 45 . One single‐center study indicated vaccine effectiveness among children with SCD ranged between −6% and 40% 46 . However, it is also possible that clinicians who encounter persons with SCD may have a lower threshold to admit patients with influenza compared with the general population.…”