I was looking at the latest Influenza Surveillance Report the other day and noticed that Arizona’s influenza epi curve has a double peak, which is very unusual. I went into the archive reports and discovered that this is the first time since 2009 with a double-peak epi curve. The double peak epi curve in ’09 was of course because of the H1N1 influenza pandemic which arrived late in the flu season and caused an unusual summer peak.
Because a double peak is such a rare event- there has to be something going on. My working theory is that a fair number of folks were still wearing face masks in public during out huge Omicron wave- which had the effect of suppressing influenza transmission. When masks dropped this spring that gave the virus a new opportunity to amplify.
I can’t prove it, but that’s the only thing that makes sense to me.
