How Do Vaccines Work?

Vaccines are scientifically backed and medically proven. They’re the best way to protect yourself and your community from severe and fatal infections. They are specially engineered to strengthen the body’s natural defense mechanisms against certain bacteria or viruses. The period of efficacy can vary between vaccine types. However, all vaccines are created to reduce the chances of getting sick from infection. Subsequently, they minimize the risk of spreading the disease to other people. But how do vaccines work, exactly?

Now, more than ever, misinformation is one of our greatest enemies. Let’s dive in.

How the Body Responds to Germs

To understand how vaccines work, it’s important to first dissect how the body’s natural immune system works.

When pathogens like bacteria, viruses, fungi, or parasites enter the body, they can cause infections and illnesses. These pathogens are made up of different parts that are unique to the disease they can cause.

The body has an immune system. It’s equipped with different types of white blood cells (a.k.a. immune cells) that fight against these disease-causing germs.

green germs and bacteria

Three kinds of white blood cells perform different tasks but work together to protect the body from disease.

-Macrophages – These swallow and digest germs and dying cells. They leave behind small parts of the germ called “antigens,” and the immune system identifies them as dangerous foreign bodies.

-B-lymphocytes – These are defensive cells that create antibodies to attack the antigens.

-T-lymphocytes – These are defensive cells that target the cells infected by the invading germs. Also called “memory cells,” they’re triggered if the same germ enters the body again.

It can take the body several days to fight off an infection. This is especially the case if it’s the first time it will encounter that specific pathogen or germ. But after the initial infection, the immune system stores the information and remembers how to combat the infection via the T-lymphocytes or “memory cells.”

If the germ invades the body again, the B-lymphocytes are ready to produce the antibodies needed to attack them. This means that the immune system can respond faster and more effectively to protect the body from getting sick.

Let’s keep going.

How Do Vaccines Work?

Schools and workplaces run fire drills and earthquake drills so that in cases of real emergencies, people already know what to do and can act quickly. Vaccines work in the same way.

how do vaccines work to fight viruses

In simple terms, a vaccine gives the immune system a practice run in defending the body against a specific virus. So, when the body encounters the disease-causing pathogen for real, the immune system knows what to do and can act quickly.

Scientists create vaccines with a version of the germ that they have modified (either inactivated or weakened). When your doctor administers your vaccine, the immune system recognizes that a foreign element (the modified germ) has invaded your body and will act on it as if it’s a full-fledged germ. Vaccines give you the best chance to fight the virus.

But Do Vaccines Technically Make You Sick?

This is a myth! The modified germ in a vaccine does not cause an illness, unlike the real thing. Rather, the vaccine imitates the infection, which triggers your immune system to learn and generate antibodies that will target the specific germ.

Because your body is learning to fight off this new foreign element and is building immunity against it, it’s normal to experience minor symptoms like fever and body pains. Once the immune system has eliminated the modified germ and the imitation leaves the body, the memory cells store the information on how to fight off the germ in the future.

However, take note that the effects of vaccines are not instantaneous. It usually takes the body a few weeks to produce antibodies and remember how to fight off an infection after vaccination. So, if a person contracts the virus just before getting their vaccine or shortly after, they can still get sick. The immune system has not had enough time to learn from the vaccine and develop immunity.

Vaccines can also differ in terms of the required or optimum dosage. Some vaccines require more than one dose because the first one is not enough to provide complete immunity. We need future doses to build complete immunity against a pathogen.

In other cases, the immunity from vaccines can slowly wear off after some time. Thus, medical professionals administer booster shots to restore immunity levels.

Achieving Herd Immunity with Vaccines

We achieve herd immunity when a significant portion of a population receives a vaccine against a pathogen. This, therefore, reduces the chances of a specific germ from circulating and infecting people.

Some people may not receive vaccination against certain pathogens for health reasons. These are typically people with compromised immune systems or serious allergic reactions to certain vaccine components. We can still protect these vulnerable people against a pathogen. This will happen if most of the people around them are vaccinated against it because the risk of transmission is low.

Vaccines don’t only protect the vaccinated from acquiring a disease. They also protect the people around you and the community at large. This includes those who cannot and have not yet gotten the vaccination.  

doctor holding vaccine injection

The Bottom Line

Given how the body’s immune system works, many believe that naturally acquiring immunity (from getting infected by a pathogen) is sufficient or better than getting a vaccine. However, most of the pathogens that vaccines fight can lead to severe health complications and even death. It’s highly risky to remain unprepared in the hopes that the immune system can simply manage it when the body encounters a serious pathogen.

Furthermore, while vaccines can lead to side effects like fever and body pains, these are typically mild when we compare them to the severe, and even fatal, effects of diseases that we can prevent with vaccines.

As the popular saying goes, “Prevention is better than cure.” Getting your vaccinations is still the best way to protect yourself and those around you against severe illness-causing viruses, including COVID-19.

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Jonathan Baktari MD

Jonathan Baktari, MD brings over 20 years of clinical, administrative and entrepreneurial experience to lead the current e7 Health team. He has been a triple board-certified physician with specialties in internal medicine, pulmonary and critical care medicine. He has been the Medical Director of The Valley Health Systems, Anthem Blue Cross Blue Shield, Culinary Health Fund and currently is the CEO of two healthcare companies.
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