Rates of hospitalizations for respiratory syncytial virus, human metapneumovirus, and influenza virus in older adults

Abstract

Background: We performed a prospective study to determine the disease burden of respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) in older adults in comparison with influenza virus.

Methods: During 3 consecutive winters, we enrolled Davidson County (Nashville, TN) residents aged ≥ 50 years admitted to 1 of 4 hospitals with acute respiratory illness (ARI). Nasal/throat swabs were tested for influenza, RSV, and HMPV with reverse-transcriptase polymerase chain reaction. Hospitalization rates were calculated.

Results: Of 1042 eligible patients, 508 consented to testing. Respiratory syncytial virus was detected in 31 participants (6.1%); HMPV was detected in 23 (4.5%) patients; and influenza was detected in 33 (6.5%) patients. Of those subjects aged ≥ 65 years, 78% received influenza vaccination. Compared with patients with confirmed influenza, patients with RSV were older and more immunocompromised; patients with HMPV were older, had more cardiovascular disease, were more likely to have received the influenza vaccination, and were less likely to report fever than those with influenza. Over 3 years, average annual rates of hospitalization were 15.01, 9.82, and 11.81 per 10,000 county residents due to RSV, HMPV, and influenza, respectively.

Conclusions: In adults aged ≥ 50 years, hospitalization rates for RSV and HMPV were similar to those associated with influenza.

Figure 1.

Eligibility and enrollment: 1042 were approached for enrollment, 591 agreed to testing of specimens for influenza alone, and of those 591, 508 agreed to further testing for other viruses.

Figure 2.

Seasonal variation of virus illness.The timeline of documented infections associated with each of the 3 viruses tested is illustrated. Data from all 3 years are included in this graph.