top of page
  • Writer's pictureserendipitous scientist

Layers of defense against COVID-19

Updated: Feb 10, 2022

Imagine a battle scene from your favorite fantasy novel. Swords are clashing. Shields are raised to block the foe’s incoming blow. The castle walls and moat act as further protection from the army that threatens to destroy the individuals behind them. Perhaps, fire-breathing dragons even fill the skies with their scaled wings!

Now that you have that image, I want to show you how battling COVID-19 is a lot like that fantastical battlefield and how multiple layers of defense are essential to overcoming the pandemic. In this scenario, SARS-CoV-2, which is the virus that causes the disease COVID-19, is the enemy that our communities are battling. Now in our nonfantastic world we won’t be battling this virus with literal swords and shields, but we do have defenses against the virus that can be compared to such weapons. Right now, the best defense we have against COVID-19 is vaccines (in the next post I’ll dive into how the vaccines work). Our other lines of defense include masks, social distancing, and air ventilation/filtration.

Let’s start with our main defense against COVID-19- vaccines. One word we often hear in conjunction with vaccines is “herd immunity”. According to the Mayo Clinic, “Herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease, making the spread of disease from person to person unlikely. As a result, the whole community becomes protected — not just those who are immune”. Let’s talk about how herd immunity is like a battlefield from your favorite fantasy novel. Imagine the vaccines are a character’s sword. Swords come in different shapes and sizes much like there are different vaccines on the market right now- Pfizer, Moderna, and Johnson & Johnson- but all the vaccines have the same goal of defending your body against the virus. Vaccines do this by training your immune system to recognize the virus that way when you encounter it in real life instead of having to take the time to train, your immune system is ready to fight immediately. There is a caveat to this however, if a person is immunocompromised (meaning their immune system is not functioning at 100%) that protection from the vaccine is decreased and, in some cases, nonexistent. Individuals who may fall under this umbrella include cancer patients, those who have autoimmune diseases like asthma or lupus, people who have received organ transplants, and older individuals whose immune systems have naturally declined due to age. Their immune systems, even with the vaccine, cannot fight off the virus. In line with our battlefield analogy, we can think of these individuals as ones who have swords, but they lack the proper training to fully wield them to protect themselves. Thus, they rely on other people who have the proper training to protect them just like immunocompromised people rely on immunocompetent people to protect them by getting the vaccine. So, getting vaccinated doesn’t protect just you it also protects the members of your community- talk about being a hero in your own story!

Our next line of defense are masks. Now one of the arguments I’ve seen is that “I’m vaccinated so I don’t need to wear a mask any longer”. Let’s discuss this argument. First, it isn’t unfounded as the CDC did at first recommended that fully vaccinated individuals didn’t need to wear masks. However, since the Delta variant (I’ll talk more about variants in a future post) is so extremely transmissible it is necessary for even fully vaccinated individuals to mask to reduce viral spread. So, yes, even if you are fully vaccinated you need to be masking up when around individuals that aren’t a part of your social bubble! Going back to our battlefield, masks can be thought of as shields in the fact that they shield people from the virus. SARS-CoV-2 is an airborne virus. This means that it can hang in the air after being sneezed/coughed/or breathed out of a person and sometimes it can linger in the air for hours. Wearing your mask protects you, but it also protects those around you since you might be the one who has the virus and is spreading it. Research has shown N95 and KN95 masks offer the best protection in protecting yourself from breathing the virus in. These masks fit more tightly around your face and are made specifically to filter out viruses. Your friendly immunologist here wears an N95. Bottom line masks work, and they are a simple way to stop the virus from winning the battle. Help “shield” yourself and your community by wearing one.

The next line of defense is our castle walls and moat or social distancing. The virus’ entire goal is to find new people to infect so it can hijack their cells to make more copies of itself so a great way to prevent that is for people not to gather. If someone is infected but stays away from other people until they are no longer infectious then the virus doesn’t have the chance to infect a new person. So, avoiding crowded areas will reduce your chances of becoming infected and from spreading the virus yourself.

Finally, our last line of defense is clean air which can be likened to archers. Remember this virus is airborne and can linger in the air for hours in poorly ventilated, enclosed spaces. The virus won’t necessarily remain in one place rather it will act like smoke and dissipate and fill whatever space it’s in. Thus, an important way to reduce transmission is to get the virus out of the air. We can do this by increasing ventilation to keep air moving indoors as well as by filtering the air with HEPA filters and air purifiers. Just like archers wipe out the oncoming army, ventilation and filtration can wipe the virus from the air making it safer for everyone in that space.

Whether fighting a battle in a fantasy novel against a deadly enemy or against a deadly virus in the real-world multiple layers of defense are vital for a winning battle strategy. We’ve discussed how there are many ways to fight COVID-19 with vaccines, masks, social distancing, and ventilation and filtration of air and how it’s important to use all lines of defense together to make the defense that much more powerful. For the next post, I’ll be discussing how the vaccines for COVID-19 work and busting some popular myths regarding them. If you have a topic, you’d like me to cover, send me an email. Thanks for reading and I hope you learned something!

16 views0 comments

Recent Posts

See All


bottom of page