Thanks for your responses. I'd seen the bit about testing w/ bicarb.
I'd been using kiwi fruit for Vit C for a few months. Worked brilliantly, several times a canker sore was emerging and eating a kiwi knocked it out. Then I got it that kiwis are high histamine, were contributing to my current unpleasant nasal congestion. Couple nights ago I used a footbath w/ ascorbic acid, and didn't need another yesterday. So I think I'll just stick w/ my footbath method for the time being. I, also, am not eager to have yet another product to fiddle with.
If there was significant impact on virus, I'd reconsider. But bad taste + fiddly means I'm happy to give it a miss.