Epidemiological characteristics and clinical severity of respiratory syncytial virus and influenza virus infections in hospitalized old patients with respiratory infection in Guiyang, 2016–2020

  Objective  To describe the epidemiological characteristics of respiratory syncytial virus (RSV) infection in hospitalized old patients with respiratory tract infections, compare the differences of clinical characteristics and severity between respiratory syncytial virus (RSV) infection and influenza virus infection, and identify the risk factors of in-hospital-death of respiratory tract infection in the elderly.

  Methods  The clinical data of 5131 hospitalized patients aged ≥60 years with respiratory tract infection in two hospitals from January 1, 2016 to December 31, 2020 were collected. We compared the differences in demographics, underlying disease, clinical symptom/sign, length of hospital stay and death during hospitalization in the elderly with RSV infection and influenza virus infection, and a multivariate Logistic regression model was used to identify the risk factors of deaths in the elderly with respiratory tract infection.

  Results  Among the 5 131 hospitalized patients aged ≥60 years with respiratory tract infections, 104 were tested positive for RSV (2%) and 497 were tested positive for influenza virus (10%). During this period, 77% (80/104) of RSV infections and 63% (312/497) of influenza virus infections occurred during November - February, showing obvious seasonality. The differences in the median of age (73 years old vs. 74 years old, P=0.997), ICU admission proportion (7% vs. 6%, P=0.822) and in-hospital death rate (6% vs. 3%, P=0.233) were not significant between the old patients infected with RSV or influenza virus. Compared with the old patients infected with influenza virus, the old patients infected with RSV had longer hospitalization length median (14 d vs. 12 d, P=0.041) and lower proportion of fever at hospital admission (50% vs. 61%, P=0.048). Among the 5131 patients, 114 died during hospitalization (2%), including 6 deaths due to RDV infection (6%) and 15 deaths due to influenza virus infection (3%). The results of multivariate logistic regression analysis showed that, after adjusting for gender and antibiotic usage before admission, age ≥80 years ［adjusted odds ratio (aOR)= 3.41, 95%CI: 1.84−14.26］, underlying medical condition (aOR=2.34, 95%CI: 1.12−4.91), interval between illness onset and diagnosis ≥7 days (aOR=8.94, 95% CI: 1.60−29.99), blood oxygen saturation <90% (aOR=4.05, 95%CI: 1.33−12.34) and RSV infection (aOR=5.38, 95%CI: 1.65−17.51) were independent risk factors of death in the elderly with respiratory tract infection.

  Conclusion  The study highlighted that RSV as an important infection increased the risk for death in the elderly hospitalized due to respiratory infection in Guiyang. Close attention needs to be paid to RSV infection in the elderly, and RSV infection surveillance, prevention and diagnosis need to be strengthened.