poor nanny,not her fault, and she did tell you she had a cold sore, and you didnt send her home
so dont think you can blame the nanny !!!!
and quite possible dc could have caught from nursery as well
im sure your nanny would have been diligent about washing hands, not kissing touching etc
i have suffered from cold sores for years, i get them when stressed,run down etc, may not have one for months, then have one, then may not have one for another 6mths
i wouldnt work with newborns with a cold sore,im a maternity nanny, but have as a nanny
In the 19yrs i was with my dh, and the almost 5yrs i have been with df i have never given either of them a cold sore