Recently, vaccines have become a popular point of controversy, specifically the Covid-19 vaccine. Terms such as "herd immunity" and "mRNA vaccine" are being thrown around more frequently than usual. But as you take the time to decide whether or not vaccination is right for you, it’s important to take a look back into history, learn the science behind these vaccines, and understand just how large the payoff can be.
Take polio, for example. Polio, or poliomyelitis, is a disease that causes severe paralysis and can even lead to death. Even so, most people in the US today don't worry about it. This peace of mind is a direct result of the polio vaccine developed in the early 1950s. This virus was disabling as many as 35,000 people a year in the United States in the late 1940s. Out of fear, children were advised to stay indoors during the summer months, travel and trade restrictions were established, and quarantines were imposed on those who fell ill. It was clear polio was a serious problem for the United States, that is, until the vaccine. The vaccine brought paralysis cases from 15,000 people in the 1950s to only 100 cases in the 60s. By 1979, polio was eliminated from the country and began to serve as an example of just how effective vaccinations can be.
Why should you get vaccinated?
There is an apparent reason you should get vaccinated. That is, of course, to protect yourself from many devastating diseases. Vaccines save as many as 3 million lives a year. However, there is another important reason why you should be getting vaccinated. Many vaccines have significantly lowered or eliminated the presence of certain diseases in countries all over the world. In fact, the smallpox vaccine eradicated smallpox from our planet. But, the decrease/eliminations of these diseases are only possible through the practice of herd immunity.
Although this may sound straightforward, eliminating a disease requires a high proportion of the population to be immune. For example, the United Kingdom National Health Service says that the UK can eliminate measles with a 95% vaccination rate among children. Yet, even a rate less than 90% can allow this virus to spread again.
The outcome of herd immunity is particularly crucial for those who cannot get vaccinated due to health complications. These people are at risk of contracting all the diseases most of us don't have to worry about, and the only way they can be protected is if the vaccination rate is high enough to stop the spread of the disease. So if you aren't willing to vaccinate for yourself, consider the people around you who could be at risk.
Are they safe?
Vaccines are no new concept. They have been around since the late 1700s and are very well researched. Most vaccines undergo years of trials, and all vaccines must undergo thorough testing to become open to the public. With all of that in mind, certain people cannot be vaccinated. For example, vaccines may not be recommended for those with weakened immune systems or severe allergies to vaccine ingredients. That being said, a severe reaction to a vaccine is not common. The likelihood is about a one in a million chance. Most reactions also happen within the first 15 minutes when you are still surrounded by trained medical professionals.
It's also important to note that some vaccines have mild side effects. Common side effects include swelling, soreness, and redness around the vaccine area, a fever, and other cold-like symptoms.
Always talk to a doctor about the health risks before receiving any vaccine or if you are worried about any side effects.
How do they work?
Before understanding how a vaccine works, you must first understand how your immune system responds to a threat naturally.
Every disease is caused by a specific pathogen. A pathogen can be a bacteria, parasite, fungus, or virus. The way your immune system fights these pathogens is similar to an army. You have the first line of defense, your innate immune system. This immune response is made up of physical barriers like your skin, nose hair, and mucus, along with two types of defense cells: your phagocytes and natural killer cells. These cells are trained to recognize the general features of a pathogen and destroy them.
If a battle against a pathogen turns serious, a specialized unit is sent in. This elite force is called your adaptive immune system. A vital part of this unit is a weapon-like protein called antibodies. Like a lock and key, an antibody has a unique structure that can bind to a particular pathogen. You have thousands of unique antibodies that allow for the recognition of a multitude of pathogens.
However, if the body has never seen a specific pathogen, it must build a new antibody that can recognize and attack it. This process takes valuable time and allows the pathogen to do damage. Once the specific antibody is made and recognizes the pathogen, it triggers the mass production of more of this antibody. Additionally, your body creates memory cells. Memory cells remember the instructions of this new antibody, so if confronted again by the same pathogen, they can recognize the pathogen, quickly produce the correct antibodies, and elicit a faster immune response.
A vaccine aims to trigger your body's adaptive immune response to these diseases. Some vaccines contain dead or weakened pathogens, while others only contain identifiable parts of the pathogen, like proteins or toxins. This means the pathogens within your vaccine can’t hurt you because they don’t work as well as a normal pathogen. However, your immune system still recognizes them as a threat.
As a result, your body believes it is under attack and begins to build an antibody to recognize this pathogen. This new antibody is then remembered by memory cells, so your body can undergo a faster response if confronted with the live pathogen in the future. The faster your body responds to these dangerous diseases, the less damage they do to your body, and in many instances, they can save your life.
Why do I have to get multiple doses of a vaccine?
Many vaccines require multiple doses. This may be due to the type of vaccine, the pathogen, or your body's response to the pathogen. A vaccine that creates a more challenging fight for your body usually results in longer immunity, and fewer boosters or no boosters may be required. If the vaccine includes a weak but live virus, your body will have to spend more time fighting it off. The more of a threat your body sees this vaccine as the longer it will remember the virus.
If a vaccine is easier for your body to fight off (non-live vaccines), your body is less likely to think of this disease as a serious threat. So, to combat complacency, you must receive multiple vaccine doses. If your body keeps encountering this pathogen, it will build better protection against it.
Some vaccines, like the flu vaccine, must be given annually. Usually, this is the case when the virus you are vaccinating against mutates rapidly. Unfortunately, a pathogen that is constantly changing won't be as easy for our immune system to recognize, so we must introduce our bodies to new variants each year.
What types of vaccines are there?
1. Live Attenuated Vaccines
The first and oldest type of vaccine is a live-attenuated vaccine. The MMR (measles, mumps, and rubella), smallpox, and chickenpox vaccines are all live-attenuated vaccines. This vaccine uses a weaker version of the actual pathogen. Still, your body does have to put up a fight. A more challenging fight means your body remembers this pathogen for longer. As a result, only one dose is typically needed.
However, a live-attenuated vaccine may not be recommended for those with weak immune systems, so it's important to talk to your provider before receiving these vaccines.
2. Inactivated Vaccines
Inactivated vaccines, like the rabies and polio vaccine, use inactive or dead pathogens. A dead virus usually doesn't create enough of a stir in your immune system to give you immunity, so multiple doses are recommended.
However, because the virus is dead, these vaccines are cheaper to make and easier to transport (they don't require refrigeration like live vaccines do). They are also generally safer for those with weak immune systems.
3. Subunit Vaccines
Unlike live-attenuated and inactivated vaccines, subunit vaccines do not contain the whole pathogen. Instead, they contain specific parts of the pathogen that our body recognizes. The three types of subunit vaccines (polysaccharide, conjugate, and protein-based) differ depending on which part of a pathogen they contain. Because of this, subunit vaccines like shingles and HPV are safer for those who cannot get live-attenuated vaccines.
4. Messenger RNA Vaccines
mRNA vaccines inject a molecule known as messenger RNA (mRNA) from a specific pathogen into your body. Messenger RNA contains instructions for building the target pathogen’s spike proteins. Spike proteins are harmless proteins found on the surface of the pathogen. As pathogenic proteins become produced, your body believes it is under attack and triggers an immune response. This immune response is triggered again when a pathogen enters the body and your antibodies recognize the familiar spike proteins on the pathogen’s surface.
There are multiple benefits to this type of vaccine. First, they are easy to make in bulk. Additionally, because this vaccine uses mRNA instead of a live pathogen, scientists can tweak the mRNA to target different variants of the same pathogen. As a result, this type of vaccine works well for a constantly mutating disease like Covid-19.
5. Viral Vector Vaccines
Viral Vector Vaccines work by injecting a harmless virus into your body. This virus holds within it instructions for making proteins specific to your targeted pathogen (the pathogen you are vaccinating against). These proteins trick your body into believing it is under attack from your target pathogen. This method triggers an immune response large enough to need only one dose most of the time. Zika virus vaccines and HIV vaccines use this method.
6. Toxoid Vaccines
Toxoid vaccines use inactivated toxins to create an immune response. This method differs from other vaccines because it does not build resistance to the pathogen but instead the toxin that the pathogen uses. Toxoid vaccines are used only when the pathogen’s danger comes from the toxin it releases. Therefore, there’s only a need to build immunity against the toxin and not the pathogen itself. Some examples of toxoid vaccines are tetanus and diphtheria vaccines. Booster shots every several years are usually necessary for this type of vaccine.
Getting vaccinated can save your life and the lives of people around you. Even if you've never heard of some of these diseases mentioned, it doesn't mean they aren't dangerous, so it's important to stay diligent and do your part.