Covid vaccines have still been much more effective against the variants that existed when they were developed, and against delta. We’re talking about over 99% effectiveness for mRNA vaccines, too. As far as omicron goes: https://amp.usatoday.com/amp/9123578002.If flu shots were taken more than once a year they would likely be more effective. Covid shots have not been out long enough to really determine effectiveness in preventing infection. Both Delta and Omicron have had an impact on effectiveness and will have to be included in any calculations in the coming year. You can’t just look back at the initial shots and say oh yay it’s 70% effective when it is now clearly nowhere near that.