In the fight against Covid (SARS-2), nose sprays haven't gotten much attention. Everyone's been yelling at each other about the big three: masks, vaccines, and clean air. So it's worth asking, does any of this stuff work?
The limited data says, yes, but...
There's hundreds of studies on the big three (masks, vaccines, clean air). By comparison, there's only a handful on nose sprays. There's a lot of personal testimony that they offer some protection.
There's a few big questions: Why do we need them? How do they work? Which one works best? Are they safe for kids?
We can answer the first question pretty quick: Most people we know have completely lost their minds over the last year and decided their sole purpose in life is to give us Covid so that they can get back to a normal that's never, ever going to exist again. Depending on where you work, you're either pressured to drop your mask, or even forbidden from wearing one. Vaccines don't reliably prevent infection and inside air for the most part is as dirty as it ever was. In a world this nuts, it's only logical to want some extra protection.
As for the other questions...
The Clean Air Club did a roundup on nose sprays earlier this year, showing that many of them offer a 60 percent reduction in risk or better. Since then, we've come across a few other brands. These sprays fall into broad categories based on their active ingredient. Here's the most common ones:
Iota-Carrageenan
Nitric Oxide
Xylitol
ELAH
Hypromellose
Astrodimer Sodium
All of these sprays work by forming a protective barrier in your nasal cavity that blocks viruses from binding with the ACE-2 receptors. Most research agrees that your nose serves as the primary gateway for infections.
It's the landing ground.
From there, you aspirate viral particles into your lungs. If you can block, deactivate, or kill pathogens in your nose, then you prevent an infection before it gets going.
Let's go through each type of spray:
Iota-Carrageenan nose sprays have the most studies behind them. They're made from a compound derived from red seaweed. Several studies demonstrate their ability to reduce or eliminate viral load in labs and real-world settings for a range of Covid variants by about 80 percent. (See below.) They work on other common viruses, too. A few different companies make iota-carrageenan sprays. Some of them explicitly say their sprays are safe for children.
Here's the info:
Iota-Carrageenan sprays are effective. They're also affordable, safe for kids, and widely available in several countries.
So, they're a good option.
Nitric Oxide sprays like Enovid get a lot of hype. There's a few studies to back them up, but these sprays also seem to have compelling anecdotal evidence. Your body already contains Nitric Oxide. It plays an important role in your respiratory and immune system, and it just so happens to also contain antiviral properties against Covid, as well as HIV, rotavirus, and adenovirus. Some hospitals have been using it to prevent and treat Covid. They seem to provide a similar risk reduction to iota-carrageenan sprays, at 80 percent.
Here's the info:
The company that makes Enovid is SaNOtize. They're based in Canada, but they manufacture the same product in India (Fabispray), Germany (VirX), and Enovid (Israel). It's technically not available in some countries, but you can order it online and have it shipped. The downside? It's expensive.
Xylitol sprays like Xlear don't give you the intense burning sensation of the other sprays. Xylitol is a natural sugar found in fruits and vegetables. A study in the Journal of Clinical Virology shows they're effective, but not quite as potent as the others with a 62 percent reduction in risk. As a bonus, xylitol sprays also boost your own body's production of nitric oxide.
They've got a good track record.
Here's the info:
On the plus side, Xlear feels good on your nose. If you've got a kid who refuses nose sprays, this gives you an option.
Nose sprays like Covixyl contain a compound called ELAH. It's been used for decades in foods and mouthwashes like Listerine. It's hard to find peer-reviewed studies on ELAH nose sprays, but it's widely recognized as effective at inactivating and killing viruses. This one seems to burn the most.
Here's the info:
Finally, there's hypromellose and astrodimer sodium nose sprays. Hypromellose sprays reduce risk by about 80 percent, and astrodimer sodium sprays reduce viral load significantly.
While you can find evidence they work, these two seem to have the fewest studies backing them. One of the companies that makes an astrodimer sodium spray, Viraleze, is concluding a human study by the end of the year. We'll bring you news on that when it's out.
Here's the info:
Now for the caveats:
None of these sprays eliminate your risk. Most people who use them also wear masks and use air purifiers whenever they can. With so much Covid in the air, it's nice to have another tool.
To get the most benefit, you need to use these sprays before and after you go somewhere. Every spray comes with its own instructions, but they all suggest using them 2-3 times a day. The idea is to make a barrier in your nose to prevent the virus from latching on and replicating.
There is also evidence that these sprays can reduce viral load during the active phase of an infection, so don't give up using them if you do test positive.
You can probably imagine why these nose sprays don't get a ton of attention. There's not exactly a powerful nose spray lobby in D.C. or London.
That doesn't mean we can't use them.
This data has convinced a lot of us to give them a shot. We could certainly use more studies, maybe even some comparative research to see which ones work best for certain demographics.
In the meantime...
Happy spraying.
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