The Good Morning Britain presenter revealed on Tuesday's show (March 16) that she's in isolation after one of her sons had a cough - one of the coronavirus symptoms.
Susanna, 49, has revealed that her family met her mum, 79, for lunch before they quarantined themselves.
But now she's scared the virus could have been passed on to her mum - who is considered high-risk as she's over 70.
Writing in her Daily Mail column, Susanna said: "While I hate missing work, naturally my biggest concern as we hunker down for our self-isolation over the next two weeks is Mum. Have I already put her at risk of the infection? The thought is agonising. But my mother is as pragmatic as ever.
Have I already put her at risk of the infection?
"I want to find out for sure whether it’s coronavirus, so we can put our minds at rest.
"Self-isolating when it might just be a cold is all right for me because I’ll still get paid — but can everyone afford to take two weeks off work when their child has a cough and they don’t?"
She added that, while she self-isolates, she's "planning calls to Mum several times a day" including on FaceTime and Skype with her children.
On Mother's Day this Sunday (March 22), Susanna said she and her boys will be doing a "FaceTime gathering to keep her spirits up".
Earlier this week, Susanna was unable to host Good Morning Britain as she decided to self-isolate with her sons.
On the daytime show, she explained: "All the children are off and we are effectively two households, because like many families we are a separated family so we have two households who have gone into self-isolation.
"I am very, very lucky, I am paid when I’m sick. There are people who are self-employed who will face this decision if one of their household is ill.
"I am in isolation with my family in order to suppress potential infection, if there are people who feel they cannot afford to do the same thing, how is that suppression strategy going to work?"
Susanna added: ""I have a perfectly normal temperature, as do all of my children. I do not have a cough, I have no symptoms. I’m not feeling fatigued, I feel 100% healthy."
At the time of writing, 104 people have died in the UK as a result of coronavirus, and it's believed that figure will rise.
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