This study was designed to determine if testing the first ∼40 nasal washings (interval) each month for 1 year, could be used as an epidemiologic tool for seasonality and prevalence of respiratory viruses such as human metapneumovirus in an adult and pediatric population in the southeastern United States.

Results of interval polymerase chain reaction (PCR) testing of 469 specimens for 8 viruses were compared with our current procedures using PCR, culture, or respiratory synctial virus antigen for all 7435 specimens (routine).

One hundred thirty-six viruses out of 469 specimens (29.0%) and 1,495 viruses out of 7,435 specimens (20.1%) were identified by interval and routine testing, respectively. Seasonal detection varied among viruses and to some degree between interval and routine testing. A higher percent of positives and dual infections were detected by interval testing of pediatric specimens, likely due to the use of PCR for viruses commonly seen in this population. Human metapneumovirus was detected in both pediatric and adult specimens between January and August.

Interval testing can be used to provide a snapshot of prevalence and seasonality of respiratory viruses, although as currently designed they may not be sensitive enough to identify the beginning of a specific virus season. Exclusive use of interval PCR testing identified several dual infections, including human metapneumovirus, throughout most of the year in Florida. A rapid turnaround time to results translates into improved infection control and improved patient care.