123. Age-Specific Patterns of Human Metapneumovirus and Respiratory Syncytial Virus Activity
Session: Oral Abstract Session: Epidemiology of Respiratory Infections
Thursday, October 3, 2013: 11:15 AM
Room: The Moscone Center: 300

Background:  Respiratory viral infection and transmission vary by age, with the greatest impact on young children and older adults. Recent studies indicate that influenza activity peaks first among older children, suggesting that they may drive the spread of influenza epidemics. It is unclear if this pattern holds for other respiratory viruses. The objective of this study was to define the time pattern of human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) activity by age group, thereby providing clues as to their transmission within the community.

Methods: We performed an ecologic time-series analysis to study the relative timing of peak HMPV and RSV activity among patients tested at 22 hospitals and more than 100 doctor's offices in the Intermountain West from 2006-2013. For each year, we defined a respiratory outbreak as the duration of weeks in which ≥90% of cases occurred. The midpoint of each respiratory outbreak was defined as the week when 50% of the total season's cumulative number of infections was reached. This analysis was performed for the entire cohort, and then separately by age group. The timing of peak HMPV and RSV activity was then compared by age group to the community midpoint.

Results: 4,569 cases of HMPV were identified, with a mean of 652±509 cases per season. HMPV activity peaked first among children 5-11 years of age; 3 days before the community midpoint (95% CI: -4 to -2). Among older adults (65+ years) peak HMPV activity peaked 23 days later (95% CI: 19 to 26) (P<0.001) (Figure). 20,172 cases of RSV were detected over the same period (mean 2,882±786 per season). RSV activity peaked first among children 2-4 and 5-11 years of age; 2 days before the community midpoint (95% CI: -3 to -2). Peak RSV activity among those over 65 lagged 20 days later (95% CI: 18 to 21) (P<0.001).

Conclusion:  HMPV and RSV epidemics peak at different times by age across multiple seasons. The earliest peaks are among infants and young children. Infections in older adults lag approximately 3 weeks later for both viruses. These findings provide evidence supporting the role of children and young adults in the spread of acute respiratory tract infections and suggest that reducing infection in these age groups may yield additional benefits, including the potential for reducing disease among older persons.

Chris Stockmann, MSc1, Krow Ampofo, MD1, Adam L. Hersh, MD, PhD1, Anne J. Blaschke, MD, PhD1, Carrie L. Byington, MD1, E. Kent Korgenski, MS2 and Andrew Pavia, MD, FIDSA, FSHEA1, (1)Department of Pediatrics, Division of Pediatric Infectious Diseases, University of Utah School of Medicine, Salt Lake City, UT, (2)Department of Pediatrics, Pediatric Clinical Program, University of Utah School of Medicine and Intermountain Healthcare, Salt Lake City, UT

Disclosures:

C. Stockmann, None

K. Ampofo, None

A. L. Hersh, None

A. J. Blaschke, BioFire Diagnostics, Inc.: Collaborator, Licensing agreement or royalty

C. L. Byington, BioFire Diagnostics: Collaborator and Grant Investigator, Grant recipient and Licensing agreement or royalty

E. K. Korgenski, None

A. Pavia, None

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