Annual estimates of the influenza disease burden provide information to evaluate programs and allocate resources. We used a multiplier method with routine population-based surveillance data on influenza hospitalization in the United States to correct for under-reporting and estimate the burden of influenza for seasons after the 2009 pandemic. Five sites of the Influenza Hospitalization Surveillance Network (FluSurv-NET) collected data on the frequency and sensitivity of influenza testing during two seasons to estimate under-detection. Population-based rates of influenza-associated hospitalization and Intensive Care Unit admission from 2010–2013 were extrapolated to the U.S. population from FluSurv-NET and corrected for under-detection. Influenza deaths were calculated using a ratio of deaths to hospitalizations. We estimated that influenza-related hospitalizations were under-detected during 2010-11 by a factor of 2.1 (95%CI 1.7–2.9) for age < 18 years, 3.1 (2.4–4.5) for ages 18-64 years, and 5.2 (95%CI 3.8–8.3) for age 65+. Results were similar in 2011-12. Extrapolated estimates for 3 seasons from 2010–2013 included: 114,192–624,435 hospitalizations, 18,491–95,390 ICU admissions, and 4,915–27,174 deaths per year; 54–70% of hospitalizations and 71–85% of deaths occurred among adults aged 65+. Influenza causes a substantial disease burden in the U.S. that varies by age and season. Periodic estimation of multipliers across multiple sites and age groups improves our understanding of influenza detection in sentinel surveillance systems. Adjusting surveillance data using a multiplier method is a relatively simple means to estimate the impact of influenza and the subsequent value of interventions to prevent influenza.

Objective Early initiation of antiretroviral treatment (ART) at CD4+ cell count ≥ 500 cells/μL reduces morbidity and mortality in HIV-infected adults. We determined the proportion of HIV-infected people with high viral load (VL) for whom transmission prevention would be an additional benefit of early treatment. Design A randomly selected sub-set of a nationally representative sample of HIV-infected adults in Swaziland in 2012. Methods Eight to twelve months after a national survey to determine adult HIV prevalence, 1,067 of 5,802 individuals identified as HIV-infected were asked to participate in a follow-up cross-sectional assessment. CD4+ cell enumeration, VL measurements and ART status were obtained to estimate the proportion of currently untreated adults and of the entire HIV-infected population with high VL (≥1000 copies/mL) whose treatment under a test-and-treat or VL threshold eligibility strategy would reduce HIV transmission. . Results Of the 927 (87% of 1,067) participants enrolled, 466 (50%) reported no ART use. Among them, 424 (91%) had VL ≥1000 copies/mL; of these, 148 (35%) were eligible for ART at the then existing CD4+ count threshold of <350 cells/μL; an additional 107 (25%) were eligible with expanded CD4+ criterion of <500 cells/μ; and 169 (40%) remained ART-ineligible. Thus 36% of the 466 currently untreated and 18% of the total 927 had high VL yet remained ART-ineligible under a CD4+ criterion of <500 cells/μL. Conclusions A test-and-treat or VL threshold for treatment eligibility is necessary to maximize the HIV transmission prevention benefits of ART.

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