Recently in the United States, six former surgeons general -  their country's leading spokespeople on public health - joined forces to write an opinion piece for The Washington Post.

They argued Robert F. Kennedy Jr. should not be in his current position as Secretary of Health and Human Services.

They accused him of endangering the health of the nation and amplifying the rapid spread of health misinformation.

Of course, Mr Kennedy's agency immediately responded... and threw accusations back at them.

So what are the ethics of speaking up versus maintaining silence? Especially when it's unclear whether speaking out will make a difference?