25. Effectiveness of High Dose Influenza Vaccine in HIV-positive Patients for the Winter 2017–2018 Season

Abstract

Background: Antibody response after high dose influenza vaccine (HDIV) approved for age ≥ 65 years, is superior to a standard-dose vaccine in HIV-infected persons. We report the effectiveness data of HDIV compared to the standard dose quadrivalent vaccine (SDIV) in our HIV clinic. Methods: We conducted a retrospective cohort study at the University of Kansas Medical Center to evaluate the effectiveness of HDIV in HIV-infected patients during the 2017-2018 influenza season. A phone survey was utilized to verify vaccination status and interval development of influenza-like illness (ILI). A modified CDC definition of ILI (mCDC ILI = fever and cough, sore throat or shortness of breath (SOB)) and a broader protocol defined ILI (PD ILI = sore throat, cough or SOB with either fever, chills, headache or myalgia) were utilized. The electronic medical record was reviewed to confirm vaccine type and influenza testing when available. Results: Of 560 HIV-infected patients in the clinic, 219 (39.1%) were available and willing to participate (197 males, 21 females, 1 transgender female). The median age was 53 years and BMI 27.2 kg/m2. Five percent had CD4< 200 cells/uL, and 13.7% had an HIV viral load > 40 copies/mL. HDIV was given to 119 (54.3%), SDIV to 77 (35.2%) and 23 (10.5%) were not vaccinated (Table 1). A mCDC ILI occurred in 8 (10.4%) in the SDIV group compared to 6 (5.0%) in the HDIV group (p=0.16). A PD ILI was reported in 16 (20.8%) in the SDIV group compared to 12 (10.1%) in the HDIV group (p=0.04). There was no difference in confirmed influenza cases between the two groups (Table 2). On logistic regression only vaccine dose (SDIV OR 2.34 95% CI 1.04-5.37, p=0.04) and age in years (OR 0.97, 95% CI 0.94-1.0, p=0.045) were associated with PD ILI. HDIV remained protective after adjustment for age. Vaccine side effects were mild and occurred in 11/77 (14.3%) in the SDIV group compared to 13/119 (10.9%) in the HDIV group (p=0.5). Conclusion: During the 2017-2018 winter season, the CDC reported an influenza attack rate of 14.7% in adults in the US and overall vaccine effectiveness of 38%. Our study demonstrated a 50% reduction in ILI with the HDIV compared to the standard-dose vaccine in HIV-infected patients. A larger prospective randomized control trial is warranted.