Knitting

Could you ask your goddaughter what she would prefer?

If you wash it you could, theoretically, infect it before giving it (unlikely in the circumstances). Your goddaughter could wash it immediately she receives it if she's worried.

How will you be able to give the shawl to your goddaughter if you are isolating ?

I would just give the shawl now, her mother will be able to leave it for several days if she feels it necessary.

Congratulations on the new baby. A worrying time for all new mothers just now.

I always wash baby clothes I knit, using gentle soap flakes and by hand. I dry them by pressing towels over them to squeeze out the moisture.

Ask your niece what she feels is best. She may want to wash it herself to be on the safe side. How premature is her baby? If he/she has arrived very early they may in the hospital for some time.

Meant to say congratulations!

Congratulations to your goddaughter and family. We had prem babies in the family 3 years ago. I washed everything in Woolite before handing it over.
Personally, now, I'd wash, dry in the sun, put in a vac bag and post it asap. A lovely present might offset some of the worry she may be feeling. Btw the NICU teams are amazing.