The burden of HMPV and influenza associated hospitalizations in adults in New Zealand, 2012-2015.

ABSTRACT

BACKGROUND: Unlike influenza, information on the burden of human metapneumovirus (HMPV) as a cause of hospitalizations in adults with acute respiratory illness (ARI) is limited. METHODS: We compared the population-based incidence, seasonality, and clinical characteristics of these two viral infections among adults aged 20 years and over with ARI hospitalisations in Auckland, New Zealand, during 2012-2015 through the Southern Hemisphere Influenza Vaccine Effectiveness Research and Surveillance (SHIVERS) project. RESULTS: Of the 14,139 ARI hospitalisations, 276 (4.3%) of 6484 tested positive for HMPV and 1342 (19.1%) of 7027 tested positive for influenza. Crude rates of 9.8 (95% CI 8.7-11.0) HMPV and 47.6 (95% CI 45.1-50.1) influenza-associated ARI hospitalisations were estimated for every 100,000 adult residents annually. The highest rates for both viruses were in those aged 80 years or older, of Maori or Pacific ethnicity, or living in low socioeconomic status (SES) areas. HMPV infections were more common than influenza in those with chronic medical conditions. CONCLUSIONS: Although HMPV infections accounted for fewer hospitalisations than influenza in adults aged 20 years and over, HMPV-associated ARI hospitalisation rates were higher than influenza in older adults, Maori and Pacific people and those of low SES. This highlighted a need for vaccine/antiviral development.