Clinical Characteristics and Outcomes in Hospitalized Patients with Respiratory Viral Co-Infection during the 2009 H1N1 Influenza Pandemic

Abstract

BackgroundThe clinical consequences of co-infection with two or more respiratory viruses are poorly understood. We sought to determine if co-infection with pandemic 2009–2010 influenza A H1N1 (pH1N1) and another respiratory virus was associated with worse clinical outcomes.MethodsA retrospective cohort study was performed of all hospitalized patients with a positive respiratory viral panel (RVP) for two or more viruses within 72 hours of admission at our institution from October 2009 to December 2009. We compared patients infected with one respiratory virus to those with respiratory viral co-infection.ResultsWe identified 617 inpatients with a positive RVP sample with a single virus and 49 inpatients with a positive RVP sample for two viruses (i.e. co-infection). Co-infected patients were significantly younger, more often had fever/chills, tachypnea, and they more often demonstrated interstitial opacities suggestive of viral pneumonia on the presenting chest radiograph (OR 7.5, 95% CI 3.4–16.5). The likelihood of death, length of stay, and requirement for intensive care unit level of care were similar in both groups, but patients with any respiratory virus co-infection were more likely to experience complications, particularly treatment for a secondary bacterial pneumonia (OR 6.8, 95% CI 3.3–14.2). Patients co-infected with pH1N1 and another respiratory virus were more likely to present with chest radiograph changes suggestive of a viral pneumonia, compared to mono-infection with pH1N1 (OR 16.9, 95% CI 4.5–62.7). By logistic regression using mono-infection with non-PH1N1 viruses as the reference group, co-infection with pH1N1 was the strongest independent predictor of treatment for a secondary bacterial pneumonia (OR 17.8, 95% CI 6.7–47.1).ConclusionPatients with viral co-infection, particularly with pH1N1, were more likely to have chest radiograph features compatible with a viral pneumonia and complications during their hospital course, particularly treatment for secondary bacterial pneumonia. Despite this, co-infection was not associated with ICU admission.

Detection of Multiple Respiratory Viruses Associated With Mortality and Severity of Illness in Children*

“…While prior studies have demonstrated association between viral co-detection and diagnosis of viral pneumonia 23 , hospitalization rates 12,15 , and the severity of illness 14 , this is the first study to demonstrate both an increased severity of illness and mortality in children presenting to the hospital with isolation of viral co-pathogens. This finding is of particular import as some studies have demonstrated no worsening in clinical outcomes in the presence of multiple respiratory viruses 20–22 .…”

Recent advances in the detection of respiratory virus infection in humans

“…Although single respiratory viruses can be detected in patients with symptoms, other respiratory viruses may also exist simultaneously. Children, especially those under 5 years of age, present with a higher frequency of coinfections 70–72 . Multiplex assays that contain more than one viral gene target in a single tube have the advantage of rapid detection of several potential viral pathogens simultaneously.…”

Correlation between Infection with Multiple Respiratory Viruses and Length of Hospital Stay in Patients from Cheonan, Korea

“…In contrast, Esposito, et al (2013) reported that the difference in LOS between single (6.9 days) and multiple infections (7.1 days) was not significant. Other studies have reported no difference in clinical symptoms, prognosis, or intensive care unit admission rates between single and multiple infections [21][22][23], with some reporting less severe disease in patients with multiple respiratory virus infections [24,25]. These results might be The present study has some limitations.…”