The information presented in this update is based on data provided by Ministries of Health and National Influenza Centers of Member States to the Pan American Health Organization (PAHO) or from updates on the Member States’ Ministry of Health web pages.
Regional Update EW 1, 2014
- North America: Influenza activity remained elevated. In Canada, ILI activity was above expected levels this week and influenza detections (28.5% positivity this week) decreased after their peak in EW 531. Influenza A(H3N2) and influenza A (not subtyped) have predominated among circulating influenza viruses, and 49 of the 55 influenza A(H3N2) viruses characterized (89%) differ from the current Northern Hemisphere vaccine strain. Detections of RSV have continued to increase since EW 44. Influenza hospitalizations continued to decrease and the majority was recorded among adults aged ≥65 years. In the United States, ILI activity (4.4%) decreased this week and remained above the national baseline of 2.2%. Influenza detections (20.2% of positivity this week) continued to decrease after their peak in EW 52. Influenza A (not subtyped) and influenza A(H3) have predominated and 227 of the 349 influenza A(H3N2) viruses characterized (65%) differ from the current Northern Hemisphere vaccine strain. Influenza-associated hospitalizations continued to increase and overall, hospitalization rates among adults aged ≥65 years are higher this season in comparison to the 2012-13 season (H3 predominant season). During week 1, the percentage of pneumonia and influenza mortality (8.5%) is above the epidemic threshold of 7%. In Mexico, ARI and pneumonia activity remained within the endemic channel. Influenza A(H3N2) has predominated among circulating influenza viruses and the states with the highest pneumonia rates this week were Jalisco, Sonora, Colima, Chihuahua and Aguascalientes.
- Caribbean: Respiratory virus activity remained low this week with the exception of Puerto Rico, where ILI activity (as reported to the CDC) remained high and influenza detections increased. Among respiratory viruses, circulation of RSV (Cuba), influenza A(H3N2) (Cuba, Jamaica), influenza B (Jamaica) and parainfluenza (Dominican Republic) was reported.
- Central America: Respiratory virus activity remained low and ARI/SARI activity were within expected levels (Costa Rica, Nicaragua). Detections of RSV have been decreasing in Costa Rica and Nicaragua since EW 50.
- Andean Sub-region: Respiratory virus activity remained low and ARI/SARI and pneumonia activity remained within expected levels (Colombia, Ecuador, Peru). Respiratory virus detections continued to decrease in Colombia and Peru while in Ecuador the detections increased in the last three weeks. Among respiratory viruses, circulation of RSV (Colombia, Ecuador), influenza A(H3N2) (Ecuador), influenza B (Colombia) and parainfluenza (Peru) was reported.
- Southern Cone: Respiratory virus and ILI/SARI activity remained low. There have been very few influenza and other respiratory virus detections in recent weeks in Argentina, Chile and Uruguay.