Epidemiological Situation

The seasonal flu epidemic in Réunion started late this year (week 35 for emergency departments and week 36 for sentinel physicians), and unlike previous years, no epidemic wave was observed earlier in the year. After a sharp increase, flu activity in emergency departments has been declining for the past two weeks. The peak was reached in week 39, at a level not seen since 2010–2016. In week 41, although the trend is downward, activity remains above the threshold and the highest values observed since 2016. This decrease in activity (subject to confirmation) is also observed among sentinel physicians. Activity fluctuated at a high level never seen during the 2010–2016 period for three weeks (w38–w40) before beginning to decline in week 41, while remaining above the epidemic threshold. This trend will need to be confirmed in the coming weeks.Severe cases requiring intensive care continue to be reported (the number observed in 2017 exceeds the peak observed between 2010 and 2015).The proportion of positive influenza test results continues to rise, with a predominance of type B viruses. Given that the epidemic remains active at a high level and due to the significant number of severe cases requiring hospitalization in intensive care, it is important to reiterate measures to prevent the transmission of influenza.