Etiology of viral respiratory tract infections in hospitalized adults, and evidence of the high frequency of prehospitalization antibiotic treatment in Norway

Background and aims Respiratory tract infections (RTIs) cause considerable morbidity and mortality in all age groups, but the epidemiology and role of several of the viral RTIs in the adult and elderly patients are still unclear, as is the extent of prehospitalization antibacterial drug use in this population. Methods We conducted a three-year (2015-2018) observational study of viral RTIs in hospitalized patients in a 500-bed hospital in Southeastern Norway, including all patients >= 18 years with RTI symptoms where one of the following viral agents was detected in a respiratory specimen (Seegene Allplex): Influenza A/B, RSV A/B, human metapneumovirus (hMPV), adenovirus and parainfluenza virus 1-4. Viral findings, demographical data, and information on prehospital antibiotic prescriptions were recorded. Results In 1182 patients 1222 viral infection events occurred. The mean patient age was 69.6 years, and 53% were females. Influenza virus A/B (63%), RSV A/B (15%) and hMPV (13%) were the most common agents detected. The proportional burden of influenza A H1 was found to be relatively high (65%) in the age groups <69 years, compared to older patients (P = .001, chi-square). As many as 20% of the patients had been treated with antibiotics prior to admission, with the lowest rate for influenza A H3 group at 17% (P = .036, chi-square), and highest for the RSV group at 28% (P = .004, chi-square). Oseltamivir was prescribed prior to hospitalization in only 3 cases (0.2%). Conclusions We found a high rate of prehospital antibiotic prescription in adults hospitalized with viral RTIs, warranting better stewardship programs to tackle the increasing antibiotic resistance problem.