Since mid-2020 as Biden won the Democratic nomination, Fox News has fixated on his age and health, consistently running twice as much coverage as CNN and MSNBC. Yet, something remarkable appears to have happened within the past month: Fox News has pivoted away and CNN and MSNBC have increased their coverage, with all three now roughly equal.
From a peak in mid-July, Fox News rapidly ramped down their mentions of his age and health through the end of last month and thus far this month, Fox News has mentioned the topics actually less than CNN and MSNBC.
In fact, Google Trends searches showed a burst of attention in mid-July and a similar rapid trail-off that matches Fox News. This once again reflects the strong correlation between news attention and search interest, even if the causative direction remains unclear.
Thus, it appears that, for the moment, questions over Biden's age and health have faded from Fox News, while CNN and MSNBC have ramped up their attention.