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

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. Disclosures Wissam El Atrouni, MD, ViiV (Advisor or Review Panel member)