LAUSR

In their study, Yue et al. reported influenza co-infection among COVID-19 patients as 57.3%. The study included a period of January 12-February 21, 2020 in Wuhan, China. We have recently detected this rate as 0.54% in Turkey. This difference between rates of co-infection can be explained by the seasonality of the influenza virus. Our study included the period of March 10-May 10. Another study from Wuhan, including the period of 28 January-29 February 2020, reported the rate of influenza co-infection among critically ill COVID-19 patients as 49.5%. Zhu et al. reported 2.7% influenza co-infections among COVID-19 patients, in their study from January 22-February 2. Two studies from USA reported low rates of 0.08% in March 16-April 20, and 0.9% in March 3-March 25. Therefore, studies from the influenza season reported very high rates of co-infection. When the COVID-19 came to Europe and America, the influenza season was almost over and thus the co-infection rates are low. A recent research found moderate to strong correlation between higher influenza vaccine uptake in the elderly and lower COVID-19 deaths in Italy. This might be explained by the prevention of influenza co-infection. In elderly, both influenza and COVID-19 have higher rates of mortality. The impact of prevention of influenza in this fragile group is higher. Current influenza-COVID-19 co-infection reports suggest that co-infection rates are as high as 57% when influenza is circulating. Pending the new waves of COVID-19, it is reasonable to recommend influenza vaccination especially for elderly, but most probably, to general population. This article is protected by copyright. All rights reserved.