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How vaccines work: Principles of operation CAN be understood

how-vaccines-work

I’m seeing a lot of people on social media make comments that reveal that they do not understand the basic principles of the operation of vaccines.

To be clear, I’m not talking about failing to understand Covid-19 vaccines or mRNA vaccines.

I’m talking about people not understanding the basic principles of operations of vaccines, in general.

How vaccines work: common indications of not understanding

I don’t know how many people I’ve seen on social media sites say variants of these two things:

  • If the vaccines work…..
  • Vaccines prevent infections, this doesn’t, so it’s not a vaccine

First, what DO vaccines do

I’ll address both those statements in a bit, but to provide a frame of reference, here is a very terse high-level description of what vaccines do, and how they do it.

And, for what it’s worth, I first learned this in grade 10 biology class, and until I started seeing those statements above show up on social media, I thought what I’m about to share was so widely known it could be considered “common knowledge”.

The distinction between what a vaccine does within an individual and what a vaccine does within a population seems ESPECIALLY poorly understood.

First, how vaccines work at the level of the individual

A vaccine is a method of training the immune system to recognize a harmful pathogen and initiate an immediate immune response.

That’s it.

The way this is done has varied over time and between diseases. And this continues to vary.

The 18th-century smallpox “inoculations” were not vaccines strictly speaking, but they were the best tool available at the time.

While the smallpox vaccine was first used in 1798, General Washington issued a mandatory smallpox inoculation for soldiers in the Continental Army in 1777.

Anyway, when a harmful pathogen enters the body of an unvaccinated person, the body’s immune system has to figure out what it is, and figure out how to kill it.

This takes time.

If the pathogen replicates itself within the body to where there is “enough” of it, the person gets sick.

And for many diseases, the risk of death was very real.

For example, with smallpox, about 30% of the people who got infected died.

When the same harmful pathogen enters the body of someone who has immunity (either from vaccination or having survived the disease), their immune system immediately recognizes the pathogen and starts to kill it.

This lessens the severity of the symptoms

This immediate response lessens the severity of the symptoms, as the level of pathogens in the body is kept to a minimum, by virtue of the immediate immune response.

This greatly increases the odds of the pathogen level in the body always being so low the infected person doesn’t get sick, even though there is some harmful pathogen in their body. There’s just too little to cause harm.

And shortens the time window in which an infected person can infect others

In addition to keeping the level of a pathogen in the body to a minimum, this also results in the body being free of the pathogen much sooner. This also results in a shorter time window in which an infected person can infect others.

And how vaccines work at the level of a population

The benefit of vaccines within a population comes from the fact that people with immunity have a shorter time window in which they can infect other people.

This is fact is THE key to eradicating a pathogen from a population.

This reduces incidents of people infecting other people

I’m going to use Covid for this example.

Research shows that when a person without immunity is infected with Covid, they become infectious up to 72 hours before they show symptoms, and stay infectious for up to 10 days after they stop. And most people with mild symptoms recover within one to two weeks.

Therefore, when a person without immunity is infected with Covid, there is a time window of 15 days to 27 days in which they can infect other people.

On the other hand, when a person with immunity (again either through vaccination or having survived the illness) gets infected, the time window in which they can infect other people is much shorter.

How much shorter? Believe it or not, the best estimate I found online is “at much lower rates“.

If all we’ve got is “at much lower rates” how do we know this reduced time window to infect others is real?

Three reasons:

  1. At the level of a population, not only is this WHAT vaccines do, it’s really ALL they do. Independent of the type of disease or vaccine.
  2. Counties in the US with very high rates of vaccinated individuals are seeing MUCH reduced spreads of the illness, which demonstrates much reduced rates of infection from person to person.
  3. Conversely, counties in the US with low rates of vaccinated individuals are seeing higher rates of the spread of the illness, which demonstrates higher rates of infection from person to person.

Which slows the replication of the pathogen within the population

The key to eradicating a pathogen from a population is that it dies in the immune system of an infected person BEFORE that person has a chance to infect anyone else.

The odds of this happening go WAY UP when almost everyone in a population has that greatly shortened window of being infectious.

This is what is called “herd immunity”.

It’s called herd immunity because it has no meaning to any one individual. It only has meaning to a population, to a herd.

Now, back to common signs of not understanding

“If the vaccines work….”

This shows binary thinking about vaccines. That they either work (are 100% effective) or they don’t (are 0%) effective.

There is no vaccine in the world that meets this standard.

This is why some vaccinated people get sick, and this is also true of EVERY other vaccine for every other type of disease.

“Vaccines prevent infections, this doesn’t, so it’s not a vaccine”

Vaccines train the immune system to start an immediate immune response to a pathogen.

By definition, vaccines CAN NOT prevent the pathogen from entering the body.

In order for the immune system to detect and start killing the pathogen, it HAS to enter the body.

Vaccines are about responding to pathogens. There are no vaccines in the world, of any type, capable of preventing pathogens from arriving.

Vaccines CAN on the other hand prevent people from getting sick, by killing the pathogens quickly.

When the pathogen load in the infected person stays “too low” and is killed quickly, the infected person doesn’t get sick, even though a small amount of the pathogen did infect them.

And now, some resources

Vaccines

This is a good overview of how vaccines work in general. It is not specific to any specific disease or type of vaccine.

Covid-19 vaccines

This is a study describing findings for several different Covid-19 vaccines.

Search for “IMMUNOGENICITY, EFFICACY, AND SAFETY OF SELECT VACCINES” to see specific data for specific Covid-19 vaccines.

mRNA

And while this blog post does not specifically mention mRNA or mRNA vaccines, a lot of people online are concerned about this. So here is an overview of what mRNA is, how it occurs naturally in every cell of every living organization, and the purpose it serves.

mRNA vaccines

And here is an overview of how mRNA is used to make vaccines.

Interview with an mRNA researcher

And here is a link to an interview with an mRNA vaccine researcher (Professor Shane Crotty) which I found fascinating.

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