北半球/温暖地域（北米）

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直近の過小評価に注意

In the countries of North America, influenza activity was still high with some indicators of influenza activity decreasing while others were stable or
continued to increase. In Canada, influenza-like activity (ILI) activity continued to increase well above the pre-pandemic seasonal average for this
time of year. Influenza percent positivity decreased and remained at the pre-pandemic seasonal average for this time of year. Cumulative influenzaassociated hospitalizations were highest in children under five years of age and adults 65 years and older. Pediatric influenza-associated
hospitalizations decreased in the most recent week but remained at levels above the typical peak of epidemic activity. In the United States (U.S.), the
percentage of outpatients visits for respiratory illness seemed to have peaked but remained above levels observed for this time of the year during the
past five seasons and was very high in some regions. The weekly hospitalization rate was highest this season in week 48 and, in comparison with
previous seasons since 2010- 2011, it was the third highest peak. Hospitalization rates were highest among adults over 65 years followed by children
under five years of age. The percentage of deaths attributed to pneumonia, influenza or COVID-19 in the U.S. increased and remained above the
epidemic threshold established from historical data, with the majority of recent mortality attributed to COVID-19 but with an increased proportion due
to influenza in recent weeks. In both countries, several respiratory viruses were co-circulating. Influenza A viruses predominated, and A(H3N2)
viruses accounted for the majority of subtyped influenza A viruses. Influenza A(H1N1)pdm09 accounted for approximately 5% of subtyped influenza A
detections in Canada and 20% in the US in the most recent week. RSV activity remained elevated in both countries and above average levels for this
time of year in Canada but seemed to have peaked in both countries.
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