Author/Authors :
Cheraghi، Zahra نويسنده Department of Epidemiology & Biostatistics, School of Public Heath, Hamedan University of Medical Sciences, Hamedan, Iran , , Doosti Irani، Amin نويسنده Department of Epidemiology & Biostatistics, School of Public Heath, Hamedan University of Medical Sciences, Hamedan, Iran , , Rezaiean، Shahab نويسنده Department of Epidemiology & Biostatistics, School of Public Heath, Hamedan University of Medical Sciences, Hamedan, Iran , , Ahmadzadeh، Jamal نويسنده Department of Epidemiology & Biostatistics, School of Public Heath, Hamedan University of Medical Sciences, Hamedan, Iran , , Poorolajal ، Jalal نويسنده Research Center for Modeling of Noncommunicable Diseases, Department of Epidemiology & Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran , , Erfani، Hossein نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Battaei، Jalal نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Zahiri، Ali نويسنده Center for Disease Control & Prevention, Deputy of Health Services, Hamadan University of Medical Sciences, Hamadan, Iran , , Noroozi، Norooz Ali نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Golshaeian، Ali نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Anvari، Mostafa نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Neshani، Ali نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Padyar، Hamid نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Alipoor، Ali Mohammad Reza نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Moradi، Mohsen نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Maleki، Mahdi نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Givi، Samad نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran , , Esmaeili، Morad نويسنده Deputy of Health, Hamedan University of Medical Sciences, Hamedan, Iran ,
Abstract :
Background: The novel influenza A (H1N1) virus was first detected in March 2009 in Mexico and then disseminated to many other countries worldwide. In this study, we assessed the potential risk factors of swine flu as well as the most important clinical manifestations of this infectious disease among confirmed cases during early phase of pandemic H1N1.
Methods: Subjects (cases and controls) were selected from those patients with signs and symptoms of respiratory tract infection who referred to health centers of eight cities throughout Hamedan Province, western Iran form July to December 2009. Characteristics of the participants were obtained by interviewers using pre-determined questionnaire. Cases were distinguished by pharyngeal soap speci-mens positive for influenza A virus using polymerase chain reaction (PCR). Logistic regression model was conducted at 0.05 significance level using Stata 9.1 statistical software to assess the effects of various risk factors on H1N1 influenza infection.
Results: Totally, 245 confirmed cases of H1N1 influenza were compared with 388 controls. Case fatality rate of influenza infection was about 2.86%. In comparison with age group of 1-19 yr old, adjusted odds ratio estimates was 1.91 [95% CI: 1.06, 3.46] for age group of 20-39 yr old, 0.94 [0.37, 2.38] for age group of 40-59 yr old, and 0.34 [0.09, 1.37] for age group of 60-79 yr old. Adjusted odds ratio estimates of influenza A infection was 8.12 [95% CI: 3.11, 21.6] for pregnant women compared to non-pregnant women; 1.84 [95% CI: 1.32, 2.86] for high educated individuals in comparison with low educated individuals; 2.11 [95% CI: 1.25, 3.57] for whose who had close contact with suspected influenza patients; and 2.15 [95% CI: 1.16, 3.98] for individuals with normal body mass index (BMI= 25-30) compared with underweight individuals (BMI < 20). There were no significant differences in clinical manifestations between cases and controls.
Conclusion: The risk of influenza A infection is highest among children and adolescents, pregnant women, high educated individuals, and those who had close contact with suspected influenza patients during pandemic phase. In addition, there is no pathogonomonic sign or symptom to distinguish influenza infection clinically from other kinds of respiratory track infections.
