Bad news is an urgent matter and people usually write off at once to tell their relatives or friends. Good news, of course, can be just as important sometimes (‘It’s a boy!’), but if we receive no news at all, we can safely assume that all is well.
‘We’ve heard nothing from Cousin Maud for nearly a year. I hope she’s all right’.
‘Don’t worry, dear. She’s probably been too busy to write to us. No news is good news.’