2013-01-29-世界卫生组织-Public_Health_Research_Agenda_for_Influenza_-_Appendix_10_10页_96kb

Summary of Influenza Infections Publications, 2010–2011

This appendix details clinical studies on influenza infections, primarily focusing on the 2009 H1N1 pandemic, published between 2010 and 2011. The studies collected data from various regions, populations, and clinical settings, providing insights into the disease's presentation, complications, and outcomes.

Key Clinical Features and Presentation

• Respiratory symptoms such as cough, fever, and shortness of breath were common in adults and children.
• Chest imaging (e.g., radiography and CT scans) revealed pneumonia in severe cases, with distinct patterns compared to interpandemic pneumonia.
• Symptoms often progressed rapidly, with a notable peak in incidence during specific waves of the pandemic.

Complications and Serious Outcomes

• Neurological complications included encephalitis, myocarditis, and strokes.
• Hemophagocytic lymphohistiocytosis, rhabdomyolysis, and acute kidney injury were reported in critically ill patients.
• Complications were more frequent in high-risk groups, such as those with obesity, malignancy, or underlying health conditions.

Risk Factors for Severity

• Factors associated with severe disease included obesity in adults, advanced age, pregnancy, and hematopoietic disorders.
• Genetic mutations, such as the D222G substitution in the hemagglutinin protein, were linked to worse clinical outcomes and increased transmissibility.
• Host factors like obesity and concurrent illnesses heightened the risk of ICU admission and death.

Comparison with Seasonal Influenza

• H1N1 pandemic infections showed similar symptoms to seasonal flu but often caused more severe disease in certain populations.
• Differences in case fatality rates and outcomes were observed, with H1N1 tending to affect younger adults and children more severely in some regions.

Outcomes and Mortality

• Mortality was higher in severe cases, particularly those requiring intensive care or exhibiting complications like viral pneumonia.
• Factors predicting poor outcomes included delayed oseltamivir treatment, advanced age, and specific viral mutations.

Overall, the studies highlighted that the 2009 H1N1 pandemic imposed a significant burden on healthcare systems, emphasizing the need for targeted prevention strategies and improved diagnostics.