As you may be already aware, there are many reports around the world where people get one of the COVID vaccines and they can still test positive for the virus. In one of my previous articles, I mentioned that the HMS Queen Elizabeth crew literally had a 100% vaccination rate, but a few months later, 100 of the 700 crew members got caught the virus despite the crew also enforcing distancing and hygiene protocols. In Europe, the least vaccinated countries actually have among the lowest cases per capita, so what gives?

The simple answer is the mucosal immune system. When one talks about the immune system, you're likely thinking white blood cells in your circulatory (and lymphatic) system. However, the immune system is far more than just your white blood cells in your blood. Your skin, eyes, and nose, for instance, are also part of that immune system and your first lines of defense. Your mucosal immune system refers to the parts of your body that secretes mucous to catch pathogens. This includes your mouth, nasal cavity, eyes, and even your digestive system.

For simplicity's sake, I just want to focus on the nasal mucosal immune system. Here's a diagram and video of how it generally functions.

Note that in the context of this diagram involves a vaccine, but the principles are similar when in the presence of a virus. Your mucous is filled with what are called IgA antibodies. If a virus enters through your tear ducts or nose, then the antibodies in the tears or mucous will catch it. The overall goal is to prevent the virus from reaching the epithelial cells because once it gets to that point, the lysogenic and lytic cycles will occur. The virus will hijack the epithelial cell's replication mechanism to make more viruses.

If it gets to that point, then that's where your blood immune system will release cytokines (think of them as chemical "alarm bells") and trigger an inflammatory response, i.e. stuffy nose, sore throat, etc.. In your nose, your body will produce more mucous and transport more antibodies to the mucosal layer to prevent more viruses from breaching the first line of defense. That way, your white blood cells do not get overwhelmed.

But what does this have to do with the article's headline? Think about how the COVID vaccines are administered and how most COVID tests are executed. The needles used for COVID vaccines are about an inch (or about 2.5 cm) long, so we're talking about an intramuscular ("in the muscle") injection. Muscles are very rich in blood vessels, so injecting medicine this way will help it take effect more immediately.

Provided that the vaccines work, your immune system should have memory B-cells who can help respond to a reinfection far more quickly than the first exposure (I explained how it works here). But we're talking about the blood immune system. When we talk about COVID testing, how do the nurses collect samples? Usually, they take a cotton swab and collect some of your mucous, but that is a different part of your immune system.

When this happened to me, it was super uncomfortable.

And that is why vaccinated people can still test positive for COVID. Because the vaccines address your blood immune system, but not your mucosal immune system, viruses can still be caught in your tear ducts or nose mucous.

There are many implications from this. It means that just because you test positive after you're vaccinated, it does not necessarily mean the vaccines don't work (though that is a debate for a separate conversation). On top of that, despite some people's attempt to stigmatize the unvaccinated as super spreaders and killers, and that they don't deserve to be treated (I'm looking at you, George Takei), vaccinated people can also be spreaders.

It sounds like I'm making an argument for mask mandates and lockdowns, but those wouldn't really solve the issue. For one thing, masks don't cover your eyes where a virus can enter through and viruses are so small that they can fit through the pores of most masks. Reestablishing lockdowns is just asking for another disaster. Depression and suicide rates went up as a result of lockdowns, the former of which can weaken your immune system. Staying inside also robs you of the vitamin D that helps maintain your immune system.

There are many people who still do not want to take any of the COVID vaccines for a variety of reasons. Their decision should be respected and people should not villainize the unvaccinated. Doing so would actually end up turning them away from the vaccine even more as I explained when I wrote about the Biden administration's cringey attempt to hire TikTokers to encourage more vaccinations. And as drugs like ivermectin and hydroxychloroquine continue to be politicized, what can you do?

This is not medical advice, but there are certain nutrients that can help strengthen your immune system in case you do catch COVID. As I mentioned, vitamin D is one of them. Ideally, you should get it from sunlight exposure as it also helps your mood, but supplements work. According to Erickson et al. (2000), vitamin D may help enhance macrophage response to pathogens. On top of that, a metadata analysis shows that vitamin D can improve a COVID patient's condition during early treatment.

There are other nutrients that can aid your immune system. You may know vitamin A for being good for eye health, but it's also really important for maintaining skin and mucous membrane integrity. Eating your leafy greens which are a good source for vitamin A can enhance your mucosal immune system. Zinc is another nutrient that may help improve the immune system by enhancing natural killer cell activity (Erickson et al.,2000). A metadata analysis suggests that it may help mitigate COVID symptoms, though the amount of data is small.

But probably most importantly of all, eat healthily (i.e. limit inflammatory foods), exercise, and get plenty of sleep.