In the fight against COVID-19, our strongest allies live inside our own blood vessels.
That’s where our immune system musters its troops at the first sign of invasion by the COVID-19 coronavirus and other disease-causing pathogens.
Any invader who gets past the body’s external defenses — our skin, our mucous membranes, the hair-like cilia linings of our respiratory system — encounters an army of specialized cells and other defenders designed to destroy foreign cells and stand guard against future attacks.
“Every infection is a race between the invader — in this case the COVID-19 coronavirus — and the body’s defensive systems that keep invaders at bay,” says Dr. William Jackson Epperson, medical director of primary care at Tidelands Health and a primary care physician at Tidelands Health Family Medicine at Prince Creek. “That’s why vaccination is so important – because it helps our immune system respond much faster and more effectively.”

Our immune system is made up of two components: Our innate and adaptive immune systems.
The innate immune system is our first line of defense against germs, responding in a similar way to all invaders in an attempt to prevent infection or kill germs quickly before they spread. In addition to our skin and other external defenses, the innate immune system includes a variety of white blood cells that attack germs but don’t remember them and thus don’t provide ongoing protection against future infection.

If the innate system is unsuccessful, the adaptive immune system takes over. It is slower to respond but can specifically target the type of germ that has invaded our body. The adaptive immune system can also recall past invaders so the body can react more quickly and effectively the next time it is confronted with a similar germ.

Here’s a look at some of the key troops within our adaptive immune system and their specific jobs:
T cells: These powerhouse cells are part of the adaptive immune system and originate in the thymus gland. Their job is to identify and eliminate cells in your body that have been infected by an invading virus. T cells come in two versions: killer and messenger. Killer T cells destroy infected cells with a chemical called cytokine. Messenger cells spread the word to B cells to activate.
B cells: These cells, which are also part of the adaptive immune system, serve as a cornerstone of the body’s adaptive immune system. In addition to producing antibodies, some of these cells – known as memory cells – store an image of attackers that provides the blueprints for antibodies to protect against future invasions.
Antibodies: These compounds, which are made of protein and sugar, are produced by B cells. Their primary job is to neutralize intruders so that other parts of the immune system can destroy them. Antibodies are specific to certain germs, comparable to a key that only fits one lock.
Through its variants, COVID-19 has remained a potent threat because of its ability to evade and short-circuit our innate immune system and overwhelm our adaptive immune system, setting off in some people a “cytokine storm” that becomes a biological firestorm attacking everything around it.

The Omicron variant’s unique mutations make it particularly good at evading our immune defenses. As a result, it is very good at swamping the immune system, particularly among unvaccinated people.
“Omicron has shown itself highly transmissible,” Dr. Epperson says. “The good news is that there are proven ways to protect yourself, starting with getting the COVID-19 vaccine and, if you’re eligible, the booster dose.”

So how does vaccination help protect someone? Think of vaccination as vital intelligence about the enemy. It brings your adaptive immune system the crucial information it needs to build up its defenses long before the enemy is at the gates.
By priming the immune system, vaccination prepares your body to fight back hard and effectively. Even if the virus slips through and causes a breakthrough infection, the fortified immune system helps keep damage to a minimum.
That’s not always the case with natural immunity – the type of immunity that can be generated after someone recovers COVID-19.

In contrast to the COVID-19 vaccine, which has been shown to produce consistently strong memory within the adaptive immune system, the adaptive immune memory created through natural infection can vary based on the severity of illness, the individual’s age and other factors, says Tidelands Health infectious disease specialist Dr. Jo-anne Klein. Because adaptive immunity is complex, there aren’t any tests that can reliably predict if previous infection will protect you from future infection. Your body’s ability to quickly ward off future re-infection can be limited, resulting in more serious illness than if you had received the vaccine.
Plus, she says, relying on natural infection comes with inherent risk because it’s impossible to be sure how your body will respond to COVID-19. Some people develop mild symptoms from COVID-19, while others suffer severe – and potentially fatal – complications.
“Ultimately, the best defense we have against COVID-19 is vaccination,” Dr. Klein says. “As we have seen across the country and world, the vaccine is very safe and highly effective.”