The Burden of Human Metapneumovirus- and Influenza-Associated Hospitalizations in Adults in New Zealand, 2012-2015.

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 2 viral infections among adults aged ≥20 years with ARI hospitalizations 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 hospitalizations, 276 of 6484 (4.3%) tested positive for HMPV and 1342 of 7027 (19.1%) tested positive for influenza. Crude rates of 9.8 (95% confidence interval [CI], 8.7-11.0) HMPV-associated and 47.6 (95% CI, 45.1-50.1) influenza-associated ARI hospitalizations were estimated for every 100 000 adult residents annually. The highest rates for both viruses were in those aged ≥80 years, of Māori 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 hospitalizations than influenza in adults aged ≥20 years, HMPV-associated ARI hospitalization rates were higher than influenza in older adults, Māori and Pacific people, and those of low SES. This highlights a need for vaccine/antiviral development.