Influenza Situation Report

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 Epidemiological Week 45, 2021

  • North America: Overall, influenza activity remained low. In Canada, respiratory syncytial virus (RSV) detections continued elevated, and SARS-CoV-2 decreased; ILI activity increased above-average levels. In Mexico, SARS-CoV-2 activity continues to decline, and RSV activity continues elevated. In the United States, ILI activity continued at low levels but increased, and influenza(H3N2) detections continue to increase. SARS-CoV-2 deaths and hospitalizations remained elevated but decreasing.
  • Caribbean: Influenza activity remained low overall and SARS-CoV-2 activity continued a decreasing trend. In Haiti, SARS- CoV-2 and SARI activity decreased to moderate levels.
  • Central America: Influenza activity remained low overall. SARS-CoV-2 activity continued at moderate levels in most countries, but in Nicaragua and El Salvador, SARS-CoV-2 activity continued elevated. Increasing RSV activity was reported in Costa Rica.
  • Andean: Overall, influenza activity remained low while RSV activity continued at moderate levels in Bolivia, Ecuador and Peru, SARS-CoV-2 detections continue to increase with low SARI activity.
  • Brazil and Southern Cone: Overall, influenza activity remained low. In Chile, SARS-CoV-2 and RSV detections continue to increase, and SARS-CoV-2 positivity increased slightly in Argentina and Uruguay.
  • Global: Influenza activity remains low, but a light increase in influenza detections is noticed in comparison with last year. In the temperate zones of the northern hemisphere, influenza activity remained at inter-seasonal levels. Both influenza A and B were detected. SARI and respiratory syncytial virus (RSV) were increased and higher than in previous years in some countries. A few influenza detections of predominately influenza A and some influenza B viruses were reported in tropical Africa. Previously increased activity in West African appeared to continue on a decreasing trend. In Southern Asia, the number of influenza virus detections reported was similar to previous seasons with detections of influenza A and B viruses.In South-East Asia, few detections of influenza A (H3N2) and influenza B were reported from Malaysia. In the temperate zones of the southern hemisphere, influenza activity remained at inter-seasonal levels, except for South Africa, where increased influenza activity is reported out of season. Elevated RSV activity continued to be registered in some countries. Globally, among influenza detections, influenza B viruses predominated. SARS-CoV-2 percent positivity from sentinel surveillance continued to decrease. Activity remained under10% positivity for all regions except the WHO Region of the Americas and Europe. The WHO region of the Americas continued a downward trend in positivity and is currently 15%. The WHO European region observed an increase of about 4% and is also now 15%. Overall positivity from non-sentinel sites continued to decrease, remaining just under 7%. While activity showed a decreasing trend among the WHO South-East Asian region non-sentinel sites, activity remained elevated and above 20%.

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