I see what you mean, yes it does make it difficult to prove a trend between periods with high rates of COVID infection and low rates of COVID infection. But pr

I see what you mean, yes it does make it difficult to prove a trend between periods with high rates of COVID infection and low rates of COVID infection. But proving such a trend is problematic regardless of what the criteria for a COVID excess death is. Simply because during a period of high COVID infection a lot of people are dying from COVID before they have the chance to die from other causes.