American commas

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I've noticed American news reports often have a comma between two things when English would use 'and',

e.g. (made up examples):
Pope Francis takes part in meeting with Muslims, Jews
Ruth Archer speaks to David, Jennifer.

Is this considered correct in American English, or a colloquialism acceptable in some registers? Are there situations when they wouldn't use it, e.g. is it ok in academic work?

I am American. It is a journalism convention used to save space in headlines, etc. It is not incorrect in this context, but should not be done in other types of writing, especially formal writing, such as academic work.

Also, in US academic writing, in a series of more than two items, the serial or Oxford comma is usually mandated or recommended by style guides.