The social media platform has issued a stiffer policy and guidelines to protect the welfare of the children against paedophiles.
YouTube says it will switch off comments on almost all videos featuring under-18s, in an attempt to “better protect children and families”.
Several brands stopped advertising on YouTube after discovering that paedophiles were leaving predatory comments on videos of children.
YouTube had originally disabled comments on videos that were attracting predatory and obscene comments.
But it will now disable comments on almost all videos of minors by default.
It said the change would take effect over several months.
Some paedophiles are leaving comments on YouTube videos since 2017.
As well as leaving obscene or sexual comments, they were also using the comments section to signal content of interest to other paedophiles.
At the time, YouTube said it was “working urgently” to clean up the site.
However, in February this year advertisers including AT&T, Nestle and Hasbro suspended their ads after more predatory activity was found.
In a blog post, YouTube said its new policy meant videos of very young children would automatically have the comments section disabled.
The move is likely to include videos of toddlers uploaded by parents, as well as short films featuring children by established YouTube stars.
Videos of older children and teenagers will typically not have the comments disabled, unless a specific video is likely to attract predatory attention. That could include, for example, a video of a teenager doing gymnastics.
This could be a helpful policy because as we all know millions of hours of footage are uploaded to YouTube every day.