COVID risk mitigation, Oct 2022

I sent this text detailing my current risk mitigation strategies out to all my in-laws. Having done this much work, I thought I should put it up somewhere on the internet, in hopes that it will find someone who is still actively trying not to catch an omnipresent immune-destroying virus, so here it is.

I think the top line is: buy a nasal spray and use it.

X expressed a little interest in having me share my risk mitigation strategies. This email should satisfy. Maybe you will not be that interested, but I have gotten to the point where I feel like I have done enough reading that it would be selfish not to share, because I think the set of mitigations outlined below can substantially reduce anyone’s chances of contracting COVID.

Talking about why one would want to minimize the number of times one contracts a COVID infection is outside the scope of this email. I’m just outlining the tactics I have put together with a goal of reducing our risk to as close to zero as possible.

And I have to acknowledge up front that the number one best risk reducing factor is not having school-age children in the house. However there are a few tips below that can help protect kids in school as well.

Please feel free to reply-all if you have anything to add or comment on. All of my strategies are subject to change and I welcome new information and opinions.

Staying outside

You know dining outside is safer and all that. You may not know how much safer. It’s been calculated to generally reduce risk by about seventeen times. Which is a lot, but it is definitely non-zero. So, other mitigations should be layered on.


If you are on the mRNA train, you may have heard that there is benefit to mixing Pfizer and Moderna over the course of your boosters.

There is also evidence that the new vaccine Novavax provides protection that is more durable against new variants than mRNA vaccines, because it does not target the most rapidly mutating portion of the virus. As you know, the new bivalent boosters target variants that are now only the direct or indirect ancestors of the many, many new strains that are currently circulating. It is possible that we are entering a phase of the pandemic where no single variant dominates, which might put mRNA boosters at a disadvantage.

In the US you are not eligible for Novavax if you have already had a vaccination with anything else. This rule may change in 2023. Novavax as a mix-and-match booster is safe and is being used in other countries. The evidence for Novavax superiority is interesting enough that I’m trying to work around the regulations to get it. Have not succeeded yet.

Regardless, the current vaccines should not be considered one’s primary defense, if the goal is not to contract COVID at all.


N95 or better. No ear loops, no KN94. These are the models Y and I rely on. The most important factor is fit: if a mask doesn’t fit your face perfectly, it is not performing as rated.

  • Flomask. Expensive up front. Then you just replace the filter in a chassis made of plastic and elastomeric material. The standard “caucasian adult” model fits Y’s face well. YMMV. I find replacing the filters a little fidgety. There are two levels of filter available — the higher level is n99, although it is not certified yet. Full testing results are available though and it looks legit. There is a kid’s version.
  • Gerson 3230. Very breathable and non-muffling for the amount of protection it provides. Beats the N95 spec but doesn’t get to N99 level. This one fits me very securely. This video is actually worth watching.
  • Wellbefore N99. The material of this mask is slightly more rigid and dense than a typical n95. When worn properly, it will eventually collect a little moisture on the inside. On my face the fit feels slightly leaky at times. YMMV. If we were talking about Ebola, though, I would choose this mask and then tape it to my face in the area where it seems a little loose.

Again, bear in mind that efficiency measurements only seem to measure the filter material, not the fit. If you get the fit wrong, it is no longer an N95. I don’t go so far as to actually do a real fit test, but I do feel around the perimeter of the mask as I inhale and exhale.

I should also mention the 3M Aura. I have not tested this one but it gets a lot of good press.

I have not gone the full elastomeric route yet, and doubt it will become necessary for me.

Obvious, but needs to be said: if you take the mask off at all to drink or eat indoors, even for a moment, you have to add other strategies to mitigate the breach.

Eye protection

There was a study that showed that people who wore eyeglasses had a small lessening of risk of contracting COVID. And goggles are now a standing reco for health care providers at the hospital I go to.

I wear Stoggles in public. They are available plain or with a prescription, and they look semi normal. Many people don’t notice they are goggles until I point it out. Which I do to underline that I have a freakish commitment to not getting COVID.

Nasal sprays

For outdoor events, I rely on a nasal spray to take the risk to near-zero. For indoor events, mask plus spray.

Carrageenan based

Forms a barrier on the mucus membranes. It’s just a seaweed derivative and is used in food. More commonly used in Germany as a defense against the common cold. Reduces chance of catching COVID by 80% — so more effective than a surgical mask alone. More effective when applied pre-exposure but has been shown to have some benefit when applied afterwards as well.

Nitric oxide based

Not just a barrier, but a virucidal, for application pre- and post-exposure. A study shows that it reduces time to negative COVID test result throughout an infection by greater than 50%, so it is knocking down the virus where it first takes hold. IIRC overall its prevention rate is a little higher than the carrageenan spray. I think of it as an “oh shit, turns out that person i just had lunch with was positive” prophylaxis.

Disadvantages are it’s a little more irritating when applied, it’s more expensive, and the brand we got ships from Israel and that can take a while.

Hypochlorous acid

This is also virucidal. You make it at home from a fairly weak solution of water, kosher salt, and white vinegar. You need a device like this to run a current through the water to transform it into HCIO, then you need some litmus paper to measure the dilution. This is a fairly powerful but low-toxicity disinfectant.

The disadvantage to making it at home is it is not stable and returns to being salt water over about two weeks. But it’s such a versatile cleaner it’s worth making. For example, we found it very effective at removing dead-animal stink from one of our dogs. I think it would probably work on skunk spray.

The way I use it as an anti-COVID measure is diluted to about 5-10 ppm in a neti pot. I dilute it with water that has been boiled and cooled, with a little kosher salt added to reduce irritation.

OTC nasal irrigation

Note that nasal irrigation of any kind, like an over the counter saline spray, is potentially beneficial, so even if you don’t make HCIO, it can be worthwhile.


Certain active ingredients in mouthwash have been tested to be virucidal against COVID. I have focused on cetylpyridinium chloride, which is in certain lines of Crest mouthwash, among others. So this is an end of day thing if I’ve been in public. I view it as an important adjunct to a nasal spray.


Air quality is important, as the White House acknowledges once in a while. If you can control airflow and filtration, it’s well worth doing. Ideally ventilated spaces can approach outside levels of risk reduction.

I have a mid-range Levoit air purifier in my office at work and run it whenever I am there. After it’s been running for a minute, I then take my mask off, unless I’m meeting with someone, in which case the mask and the Levoit both stay on.

I do not ask anyone to wear a mask at this point.


I don’t worry about contracting COVID from surfaces. The risk seems very low. But soap and water don’t hurt.