Why Vaccination Programs Work

Herd Immunity: Why your vaccinations help others

True or false: In order to prevent the spread of contagious diseases such as the flu, an entire population needs to be vaccinated.


The reason this is false is that vaccination does not need100% compliance. If it did, it would be ineffective, since such compliance is virtually impossible. Instead, vaccination relies on something called herd immunity.

To understand herd immunity, imagine a community (or “herd”) that is composed entirely of people who have no immunity to Disease X, which is highly contagious.

Now imagine that just one person who was exposed to Disease X enters the community. This person, known as “Patient Zero” in medical circles, will transmit the disease to everyone they come in contact with, who will then transmit to everyone they come in contact with.

It is easy to see that in a short amount of time, everyone in the community will be exposed to Disease X.

But what happens if half of the community is immunized against Disease X? Patient Zero will then infect only half the people they come in contact with. Disease X will still spread through the community, but far more slowly, and it will infect much fewer people.

And — importantly — it is not only the people who are vaccinated who are protected.

Let’s try one more thought experiment:

Imagine that Patient Zero only comes in contact with one person (let’s call them Person One), and Person One is the only person who comes in contact with one other person, whom we will call Person Two. Let’s also imagine that, unfortunately, Person Two cannot be vaccinated for some reason. Perhaps they are allergic to the vaccine, or have some other contraindication.

Person One will not come down with Disease X, despite continued contact with Patient Zero, because they were vaccinated. But not only is Person One immune, Person Two is immune as well.

Why? Because they only come in contact with Person One, and Person One cannot transmit the disease because they were vaccinated.

We don’t live in three-person communities, but it should be clear how this concept scales to the real world. The people who are vaccinated provide a sort of protective barrier between infected people and unvaccinated people.

This means that less than 100% of a community needs to be immunized against a disease to provide near-complete protection for the entire community. How much less? That depends on how contagious the disease is.

Still confused? Well, if a picture is worth a thousand words, a video must be worth at least ten thousand. Watch the simulation below to see how a disease spreads through a population, depending on what percentage of that population is vaccinated.

And if you think that you don’t need to get vaccinated against the flu, and can just rely on herd immunity, let’s do one last thought experiment:

Imagine if everyone thought that.

That’s right, no one would be immune, and our communities would be ravaged by the flu and other contagious diseases.

So don’t just be one of the herd. Get vaccinated.

Beacon of LIFE, in Oceanport, NJ, is a government-approved PACE program created to provide seniors, their family, caregivers and professional health care providers the flexibility to meet their health care needs while continuing to live in their community.

Our clients visit our center daily, for meals and activities, as well as for medical treatment. That allows us to ensure that each client is appropriately protected against the flu, a disease that is especially dangerous for the elderly.

Moreover, Beacon of LIFE maintains an interdisciplinary team of professionals who give each client the coordinated care they need. Our staff specialize in working with older people, and work with each client and their family to develop the most effective plan of care.

We provide a variety of services, including primary care, hospital care, medical specialty services, prescription drugs, nursing home care, emergency services, home care, physical therapy, occupational therapy, adult day care, recreational therapy, meals, dentistry, nutritional counseling, social services, laboratory / X-ray services, social work counseling, and transportation.

Our care and services allow people who would otherwise need to live in a nursing home to live where they want — in their own communities, in their own homes.

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