Research on influenza epidemic and clinical characteristics based on influenza research database.

Objective: To compare the epidemic trends of different types of influenza viruses and the clinical characteristics of patients, so as to provide reference for influenza prevention and control.

Methods: This was descriptive research. The human monitoring data collected from the Influenza Research Database (IRD) from 2006 to 2016 were used to descriptively analyze the distribution of influenza viruses in terms of time, geography, gender and age. The positive samples were divided into three groups based on the type of pathogen (H1N1 influenza A viruses, H3N2 influenza A viruses, and influenza B viruses). Compared and analyzed the distribution and clinical characteristics among groups.

Results: There were statistically significant differences in the positive rates among different countries (p< 0.001). The proportion of positive samples gradually decreased with age. The proportion of oseltamivir resistance was significantly higher in H1N1-positive patients compared with that in H3N2-positive patients (p< 0.001). Significant differences were observed in the vaccination status among H1N1, H3N2 and influenza B viruses (p< 0.001). Cough was common in all cases with H1N1, H3N2 and influenza B infections, while cough, fever and running nose occurred more frequently in influenza B-positive cases than those of H1N1-positive and H3N2-positive cases (p< 0.001).

Conclusion: People aged 0-18 years are the major susceptible population to influenza, and H1N1 influenza viruses are the main pathogens of infection in this population, with major clinical manifestations of fever, cough and headache. The findings in this study highlight the necessity to strengthen the protection for this age group in clinical practice.