When is the last time you lost your sense of smell and taste from Flu? Etc etc. Symptoms were quite different than the flu.
And counting all my family members and 50 friends, way more than 50% had it. I was very conservative when I said 50%.
This is definitely some availability bias. A more systematic way of doing this (though also not scientifically sound), would be to go through your shul membership list and see if you can count 50%. You cant count 50, assume you have 100 in the population, and come up with a prevalence.
Or at the very least - take a random sample of people in your shul list, and see who had it within that sample. In stats, you can only determine prevalence when starting with a cohort not with a case.