An edited version of the swiss cheese model tailored towards the measures that you as an individual can take to minimize your risk of infection. Public health is ultimately what its name implies, public, but that doesn’t mean you’re powerless.
Covid prevention is not all-or-nothing. Think of it as risk reduction, rather than a binary.
Let’s go through these step by step.
VACCINES
The current vaccines are meant primarily to reduce chances of severe illness, hospitalization, and death. They will reduce your chance of infection a bit–but not nearly as much as you might think. You should still get your boosters regularly, because avoiding severe illness is of course worth doing.
If you haven’t gotten the updated monovalent vaccine yet, go get it. It is not a booster. Think of it as a new vaccine. It’s targeted towards the XBB lineages, which are now the most common variants. Your last boosters were likely of the bivalent type, aimed at both the original Covid strain from 2020 and Omicron. The new vaccine is monovalent, meaning it targets one family in particular.
Somestudiessuggestthat the Novavax vaccine, which is a more traditional protein-based vaccine, is more effective and safer than mRNA vaccines, and offers better protection against future variants. Of course, the data we have so far isn’t 100% conclusive (the last paper I linked is a preprint). Make of these findings what you will, just something to keep in mind. The new Novavax vaccine’s availability is still limited, especially outside of the US.
MASKS
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Masking is one of the most effective ways to protect yourself. While it is true that masking and reducing Covid transmission protects those around you, the idea that masks can’t protect the wearer is outdated information from the early days of the pandemic when medical authorities refused to acknowledge that Covid is airborne.
The key to protecting yourself is to wear a well-fitting respirator. You want to minimize any gaps where air might leak out. If your glasses get fogged up, that’s a sign that air is leaking.
Headbands will always have a tighter fit than earloop masks (and therefore provide better protection). However, you can use earloop extenders to improve the fit of earloop masks. You can find these online. Your comfort in wearing a mask is important, but there are options for compromise.
The above graphic doesn’t include elastomeric respirators. While some (like the Flo Mask) are expensive, they can be much more affordable than buying disposables–look for P100 respirators at your local hardware store, but make sure it fits your face well.
For situations where you need to hydrate but don’t want to take your mask off, consider the SIP valve.
Not even N95s are foolproof (N95 means it filters at least 95% of particles–with the other 5% potentially reaching you). Most people will likely not have a perfect fit. There will be situations where you’ll have to take your mask off. The key is risk reduction, and that’s why the Swiss cheese model is crucial.
If you can’t afford high-quality masks, look for a local mask bloc or other organization that gives out free masks. Project N95 has unfortunately shut down. In Canada, there’s donatemask.ca.
AVOID CROWDED INDOOR SPACES
This is rather self-explanatory. Indoor transmission is much, much, much more likely than outdoor transmission. If it’s possible to move an activity outdoors instead, consider doing so.
If possible, try going to places like stores or the post office during less busy hours.
Viral particles can stay in the air for a considerable amount of time even after the person who expelled them has left. Do not take off your mask just because no one is currently present, if you know that it was previously crowded.
A CO2 monitor is a decent proxy for how many viral particles may have accumulated in the air around you. The gold standard is the Aranet4, but it’s expensive, so here are some more affordable alternatives.
VENTILATION AND AIR FILTERS
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Ventilation is effective for the same reason that outdoors is safer than indoors. If it’s warm enough, keep windows open whenever possible. If it’s cold, even cracking them open occasionally is better than nothing. Try to open windows or doors on different sides of a room to maximize airflow.
HEPA air filters can significantly reduce viral transmission indoors. Make sure to find one suitable for the room size, and replace the filters regularly. You want to look for devices with HEPA-13 filters.
You can use websites likethese to calculate how long it takes for a device to change all the air in a room. Remember what I said about viral particles being able to hang around even after people have left? If an air purifier provides 2 air changes per hour, that means that after 30 minutes, any potential viral particles should be gone.
If you can’t afford a commercial air filter, here’s a useful DIY filter you can make with relatively simple materials. The filtration capacity is great–but due to being built with duct tape, replacing filters will be a challenge.
If you have to hold meetings or meet with people at work, having a smaller filter on the desk between you will also reduce chances of infection.
As a bonus, HEPA filters will also filter out other things like dust and allergens!
REDUCE LENGTH OF EXPOSURE IF EXPOSURE IS UNAVOIDABLE
Viral load refers to the amount of virus in a person’s blood. If you’ve been exposed to someone with Covid, how much you’ve been exposed matters.
You might escape infection if the viral load you’ve been exposed to is very small. Or, even if you get infected, there will be less virus in you overall, leading to milder illness–and crucially, a lower chance of the virus penetrating deep into your body, creating reservoirs in your organs and wreaking long-term havoc.
A low viral load is also less contagious.
This is the same reason that wearing your mask most of the time, but having to take it off for eating, is still much better than not wearing your mask at all.
RECHARGEABLE PORTABLE AIR FILTERS
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You might attract some odd looks. But if you’re at high risk or just want to be as protected as possible, small portable air filters can help. Try to find models small enough to take with you on public transportation, to school, or while traveling.
These devices will be far too small to clean the air in the whole room. The goal is to have it filter air in your immediate vicinity. Be sure to angle the device so that the air is blowing in your face.
Unfortunately, rechargeable devices are much rarer and harder to find than normal air filters, and many are also expensive.
The best option at the moment, apart from DIY (which is possible, but you need to know what you’re doing), seems to be the SmartAir QT3. The size and shape are a bit clunky, but it fits in a backpack. Its battery life isn’t long, but it can be supplemented with a power bank.
NASAL SPRAYS
There’ssome research that suggests that some nasal sprays may be effective in reducing risk of infection by interfering with viruses’ ability to bind to your cells.
These sprays are generally affordable, easy to find, and safe. The key ingredient is carrageenan, which is extracted from seaweed. So there are no potential risks or side effects.
Be sure to follow the instructions on the packaging carefully. Here’s a video on how to properly use nasal sprays if you’ve never used them before.
Covixyl is another type of nasal spray that uses a different key ingredient, ethyl lauroyl arginate HCI. It also aims to disrupt viruses’ ability to bind to cell walls. Unfortunately, I think it’s difficult to obtain outside of the US.
CONCLUSION
None of the methods listed here are foolproof on their own. But by layering them, you can drastically reduce your chances of infection.
The most important layers, by far, are masking and air quality. But you should also stay conscientious when engaging with those layers. Don’t let yourself become complacent with rules of thumb, and allow yourself to assess risk and make thought out decisions when situations arise where you might have to take off your mask or enter a high-risk indoor area, such as a hospital.
Remember that the goal is risk reduction. It’s impossible to live risk-free, because we live among countless other people. But you can use knowledge and tools to keep yourself as safe as possible.
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