There are a number of things you can add to saline nasal sprays or nasal rinses to
give them better antiviral properties:
iota carrageenan gum powder, 1.2% solution,
For data on this see: Iota-carrageenan neutralizes SARS-CoV-2 and inhibits viral replication in vitro, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237480
A drop of Povidone-Iodine,
For data on this see: The Effect of Povidone-Iodine Nasal Spray on Nasopharyngeal SARS-CoV-2 Viral Load: A Randomized Control Trial https://pubmed.ncbi.nlm.nih.gov/34724213/
A drop of the original Johnson's Baby shampoo
Xylitol powder
What's in the basic saline sinus rinse?
A basic Neilmed sinus rinse kit consists of 2g NaCl + 0.5g Soda Sodium Bicarbonate to be dissolved in 250ml of previously boiled sterile water. That's 2g of table salt and 0.5g of baking soda in water. The baking soda is in the mix to make the solution more gentile to your nose. You add one of the above antivirals to improve the effect.
Comparison
What are the differences between the above antiviral agents? All of them work and some are more studied than others.
Iodine results is a brown solution that can stain things. Iodine evaporates slowly at room temperature so over time any stains will simply disappear but it may take a few days. Iodine is quite aggressive and it may be irritating. Occasional short term use should not cause any problems. You will have an iodine smell
in your nose for a few hours.
Johnson's Baby shampoo works for unknown reasons. It's not exactly clear which component in this shampoo
does the trick. Johnson & Johnson may change the formula without notice. It's not well studied. The shampoo has a smell and it remains in your nose. The solution may foam a bit.
Xylitol dissolves easily and does not have any smell or cause stains. Not many studies have been done with it. The evidence of it working is currently small.
Iota carrageenan is a vegan alternative to gelatine. It does not stain and it does not have any smell in low concentrations. It's a little tricky to dissolve in hot water. This is in my opinion the best of all the antivirals.
How to prepare a sterile 1.2% Iota Carrageenan solution
Normal drinking water may contain all kinds of living organisms despite chlorination. It's safe to drink but it's not safe for rinsing your nose. You must boil it before using it.
Boil the water and let it cool down to room temperature before you rinse your nose with it.
The Neilmed bottles hold about 250ml of water (one US cup). To make a 1.2% solution you need
0.3g of Iota Carrageenan powder + 2g table salt + 0.5g baking soda.
We use a 1.2% solution because that was tested to work and is known to be safe for regular use. However
it does not have to be that exact. It's enough to get it approximately right. Here is a visual representation
of the amounts you need for 250ml of water:
Left to right: table salt, baking soda, Iota Carrageenan powder
Iota Carrageenan dissolves easily in cold water but needs to be stirred into hot water to make it gel and to get the antiviral effect. The best way to do this is to pre-dissolve all 3 powders in a bit of cold water (a few tea spoons of water) and then stir this into hot water. Bring 240ml of tap water to a rolling boil then turn the heat off. Mix 0.3g of Iota Carrageenan + 2g table salt + 0.5g soda powder with about 10ml-20ml of cold tap water. Stir this concentrated cold solution into the hot water. This will result in a slightly cloudy solution. Let everything cool down to room temperature before you use it.
Always use a fresh solution. This solution contains no preservatives and will go bad over time. A freshly prepared solution should be used within 3 days.
Nasal spray bottle and Neilmed sinus rinse bottle
The Neilmed sinus rinse bottle works much better than a small nasal spray bottle but you could use the nasal spray bottle if you are traveling and on the road. The Neilmed sinus rinse shoots up a lot of water into you nose and cleans the nose cavities really well. You shoot it up through one of the holes of your nose and the liquid will come out of the other hole. Have some paper tissues available to blow your nose. It's a bit messy but it clears your nose.
