By Peter Manley
A little over a hundred years since the disaster of the influenza pandemic of 1918, we are now being hit by yet another pandemic. In a matter of only a few weeks, life, as we know it, has been disrupted for everyone. What used to be normal activities––such as going to the gym or grabbing a drink after work––have now been postponed indefinitely, thanks to the rapid spread of the novel coronavirus (COVID-19). In short, life has been forced to a sudden and indefinite pause for just about every person on every continent, at least for the meanwhile.
But while times may indeed seem grim, the great news is that health officials and scientists have been hard at work, learning about the coronavirus with hopes of soon developing a safe and effective vaccine. Naturally, scientists have spent time analyzing how our immune systems react to the COVID-19 infection. What has been the most pressing question is: why does the same novel virus cause dramatically different outcomes from patient to patient? After all, not all people who are infected develop respiratory illness, and some patients show little to no symptoms of the novel coronavirus at all.
Thanks to intensive research and studies on actual patients who’ve been infected, we now have a better understanding of how our body reacts to the virus and why some people have it worse than others. For the sake of education, let’s take a deeper look at how the immune system reacts to the coronavirus, and what it means for our future.
The Initial Response
When you’re first introduced to COVID-19, your body will respond to it in the same way it would with virtually any other virus. First, the immune system releases interferons, which are protein molecules that work against the virus’s ability to grow and duplicate within your cells.
The interferons are also responsible for “calling” on available immune cells to attack the virus to further prevent the spread. In most cases, such as with the common cold and minor illnesses, this initial response is effective enough to control or eliminate the threat.
Furthermore, this initial response causes the typical symptoms you’d experience when you’re sick. You develop a fever to alert your body that a foreign threat has entered, and you cough or have diarrhea in an effort to rid of the harmful virus.
However, more serious viruses––such as COVID-19––are usually able to defend against this initial response.
It’s also worth mentioning that viruses affect each person in different ways depending on where it “settles”. If a virus sets up camp in your digestive system, you’re more likely to develop diarrhea and digestive complications. If the virus sets up camp in your lungs, you’ll experience respiratory issues, such as trouble breathing.
Scientists have learned that the novel coronavirus enters into a cell by grabbing onto the ACE2 receptor, which lies on the surface of a cell. These receptors exist more abundantly in the lungs and the intestines, which indicates why some of the most common symptoms of COVID-19 include respiratory illness and diarrhea.
The Second Line of Defense
If the initial immune response doesn’t work on the coronavirus, the immune system continues its efforts with a secondary yet more advanced response. In this virus-specific response, the body creates antibodies and T cells that are specifically aimed at killing and neutralizing the virus threat. Also, these antibodies that the body creates are what help prevent you from being infected again by the same virus.
Unfortunately, if someone is exposed to a high amount of the coronavirus at once, the virus can spread quicker than the body can ramp up for this virus-specific response (this is why doctors experience more severe symptoms compared to others). Aside from this, how well a person’s body handles the infection depends on the strength of their immune system as well. Older people and people with chronic illness tend to have compromised or weaker immune systems, which may result in the virus spreading throughout the body rapidly and without much of a fight.
The Issue With the Immune System
Basically, if your body is able to make enough antibodies and T cells before the virus spreads, you’ll be able to recover from and overcome the coronavirus illness. It may take a week or weeks, but you’ll generally be able to recover.
However, while the virus definitely causes damage to the body, even more damage is caused directly by the immune system itself as it tries to kick into a higher gear. In the majority of cases reported, the immune system kicks into a healthy higher gear, developing more antibodies and T cells and eliminating the virus. But for the most severe cases––which typically involve pneumonia, extreme illness, or even death––the immune system goes haywire and wreaks havoc on the body.
If the immune system overreacts and becomes hyperactive, it begins to produce an excessive number of cytokines (inflammatory proteins) in hopes of eliminating the coronavirus. Unfortunately, the excessive presence of cytokines causes a large number of cells in the lungs to die, which results in worsened conditions, severe infection, or even death.
The Best Course of Action
So what does all this mean? Basically, it explains why the elderly and those with compromised immune systems tend to experience the worst conditions. It also shines a light on the fact that while the novel coronavirus definitely causes its own fair share of damage on the body, the immune system is, unfortunately, the culprit in the most severe cases.
So what can you do? Well, for now at least, the solution remains the same. Wash your hands and keep your living areas clean and sanitary. Regardless if you are more or less at risk, we should all be practicing social distancing as much as possible. But while we’re spending more time at home, this doesn’t mean we should fall into unhealthy habits of overeating and/or not exercising. Use this time to get enough sleep, exercise at least thirty minutes a day, and eat healthy foods. These measures will work to strengthen your immune system over time...and every bit counts.