[Ahnya]

using shield is too exaggerating
but can try
https://shopee.sg/Xlear-Xylitol-Saline-N...3c8e11fbe7&xptdk=b61ed64b-22fb-4913-b888-783c8e11fbe7

https://shopee.sg/Pirdal-Nasal-Spray-15m...6b8b4d74ee&xptdk=0f8936de-41d4-44d9-9f1c-856b8b4d74ee

or wash nose with salt[font=Roboto, 'Helvetica Neue', Helvetica, Arial, 文泉驛正黑, 'WenQuanYi Zen Hei', 'Hiragino Sans GB', '儷黑 Pro', 'LiHei Pro', 'Heiti TC', 微軟正黑體, 'Microsoft JhengHei UI', 'Microsoft JhengHei', sans-serif]lt[/font] water 
www.nature.com/articles/d44151-021-00079-x
Hydrated salt could block the growth of SARS-CoV-2 - Nature
8 Dec 2021 ... The infected cells were then exposed to a non-toxic concentration of the salt. The salt exposure stopped the virus replicating. Molecular ...

There is salt rinse available from pharmacies  ( for sinus problems,  not covid) .
You can make your own salt nose rinse. There are instructions on the net, including from our cheng hu (but not in connection with covid).
I haven't tried making it. I only use a nasal spray ( but not for covid) cos I seem to be allergic to the commercially available salt rinse (it is not 100% salt and water)