Factors affecting the development of influenza infection in the elderly

Objective: Old age carries a risk in terms of infections due to chronic diseases and immune system-related problems. Respiratory viral infections, especially influenza, are important due to close contact and person-to-person transmission. In this respect, our study aimed to evaluate the personal characteristics, lifestyle and habits, and living conditions that play a role in the development of acute respiratory tract infections in the elderly. Materials and Methods: Our study was planned as an observational, analytical, case-control study. The population of our study consists of those 65 years of age and older with symptoms of acute respiratory tract infection and healthy elderly people aged 65 and over (control group) who applied to the Aydın Adnan Menderes University (ADU) Hospital, Chest Diseases Outpatient Clinic. During the 2019-2021 influenza season, nasal swab was taken from 65 patients who applied with acute respiratory tract infections in our university from Department of Chest Diseases, and 65 healthy control subjects. Samples were analyzed using PCR methods. The data were collected by a standard questionnaire created by the researchers targeting the features may pose a risk for infection. Descriptive statistics, chi-square, Mann-Whitney U and Kruskal Wallis tests were used for the analysis of the data. Results: In the study population, whose mean age was 73.59, the higher mean age was found in the cases compared to the controls (p=0.001). The rate of influenza detection in the nasal samples of the case group reporting respiratory symptoms was 26.15%, and the age distribution of the groups was found similar. There was no difference between the subjects with and without influenza in terms of the characteristics of the study, other than ownership of the house, presence of chronic diseases, liver diseases, and nutritional supplements. The factors that may be effective in the development of acute respiratory symptoms and were found to be significant were evaluated with logistic regression modelling. While the risk ratio of advanced age (OR:1,069) in the development of acute respiratory infection is relatively low, the risk of chronic respiratory disease was found to be 10,308. In addition, the risk ratios for other factors that are effective in the development of acute respiratory infection were found to be 3.269 for low income, 3.170 for city and district life, 3.709 for school-age children at home, and 4.124 for hobbies in the crowd. Conclusion: It was determined that chronic respiratory disease other than age, and some sociodemographic characteristics may also play a role in the development of acute respiratory tract infections in the elderly. In addition, it was concluded that lifestyle, nutrition and hygiene habits may have different effects on the development of respiratory infection. Key words: Acute respiratory tract infection, influenza, risk factors, elderly individuals