Only travel during lockdown if there is an 'extreme risk to life'
Dr Jenny Harries refused to comment when asked if Dominic Cummings's actions undermine the "stay at home" message.
She told the press conference: "In relation to the advice to the public, it's absolutely clear that public health guidance is, if you're symptomatic you stay at home, take yourself out of society as quickly as you can with your family and stay there, unless there is extreme risk to life.
"That is a really important message, people have been really good at doing that, but it's vital that we continue to do that going forward.
Daily briefing
Clarifying guidance about travel during lockdown, Dr Jenny Harries said it was "clear" someone with symptoms should self-isolate along with their family.
Dr Harries added that "built in" to all guidance to protect the vulnerable "there is always an element which says safeguarding".
She said: "So we don't want an elderly person sitting at home without their medication because they feel they can't come out."
Dr Harries said if there was a "safeguarding issue" where a child had "no support", that was also an issue.
"There's always a safeguarding clause in all of the advice," she said, adding: "The interpretation of that advice is probably for others.