Thank you...I bought it but didn't end up giving it to him, just took him off sugar and dairy which always seems to help.

I have contacted both companies. Emergen-C told me no pn or tn in their facilities. Airborne told me this:

Thank you for your interest in Airborne Products.
The facility that manufactures the Effervescent and On The Go formulations are made in a facility free from the following ingredients:
Peanuts
Tree Nuts
Flax or Flax Seed
Sesame
Sunflower Seeds
Egg Whites
The Chewable product contains none of the 8 allergens nor are they used in the manufacturing process. The components above may be ingredients in other substances used in the chewable facility.
If you have any further questions, please call us at 1-800-590-9794.
Thank you,
Michelle-Airborne Customer Service

Maybe too late, but I have not called on these.  Dd has triedEmergen-C.   PN/TN allergies.  She will not use because she does not like the taste.  We have 3 flavors and she loves other sweet drinks, seltzers, pop rocks, lol.  How can she not like these fizzy, fruity drinks?  Anyway, she did try them a few times and was fine, but I did not call. 

In terms of fighting off colds. I think they help me.  I use Emergen-C.  I got a cold on Sunday this week, and felt horrible.  I have used this once or twice a day since and am almost over the cold.  6 days or so.  That is very fast for me.  My throat/chest are a bit froggy, scratchy, but really, was mild after the first few miserable days. 

DS thinks he is coming down with a cold vs. increase seasonal allergies.  I'd like to boost is Vit C intake.  Does anyone use Airborne Kids or Emergen-C for kids?  Or called on these? DS is allergic to tree nuts and sesame.