The graph above shows the Influenza cases in Japan for the last 10 years (fiscal year 2011-2020, weekly reported cases). Means, after everyone began to wear a mask, wash his/her hands and avoid crowded places, the flu was almost destroyed. On the other hand, the COVID-19 pandemic doesn't seem to end still now, as you know.
上図のように、皆がマスク・手洗いをして3密を避け始めたら、インフルエンザはほぼ根絶された。しかし新型コロナウイルス(COVID-19)の流行は止む気配がないというのは皆さんご存知の通り。