We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Herd Immunity?

Mary McMahon
By
Updated Mar 03, 2024
Our promise to you
The Health Board is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At The Health Board, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

In immunology, herd immunity refers to a situation in which a high percentage of a population is immune to a disease, essentially stopping the disease in its tracks because it cannot find new hosts. You may also hear this concept referred to as “community immunity.” The threshold for herd immunity varies, depending on the disease, with more virulent agents requiring vaccination of a higher percentage of the population to create the desired immunity. In addition to being used in disease prevention, community immunity is also utilized to fight ongoing outbreaks.

Most vaccination policies are focused on creating community immunity. Many countries require vaccinations in childhood, for example, protecting children from common diseases and ensuring that when these diseases enter the population, they cannot prey on children or adults, who have been previously vaccinated or exposed to the disease. The creation of herd immunity is especially important in crowded environments which facilitate the spread of disease, like schools.

Immunologists try to prevent the outbreak of diseases by creating widespread immunity, but they are not always successful. Sometimes a disease mutates or is entirely new, or a batch of vaccinations is faulty, or a large percentage of the population fails to get vaccinated, creating a situation in which an outbreak can occur, because much of the population is vulnerable. In the event of an outbreak of a major disease, agencies like the World Health Organization (WHO) can dispatch teams within days to figure out the cause of the outbreak and develop a vaccine, in the hopes of creating herd immunity to halt the outbreak in its tracks.

For some diseases, immunity thresholds are as low as 50%, especially when combined with good hygiene. In other instances, up to 90% of the population may need to be vaccinated to create the desired protection. It is also extremely important to receive regular boosters, as some vaccines lose their efficacy over time, leaving people vulnerable to an outbreak. Herd immunity led to the eradication of smallpox, and it explains why diseases such as polio and diphtheria are rare in developed nations with established vaccination policies.

The concept of herd immunity is often used to encourage reluctant parents to vaccinate their children. In addition to ensuring that their children are protected from fully preventable diseases, childhood vaccinations also benefit society at large by creating widespread protection from disease. Likewise, adults may be reminded to receive boosters to help protect their communities.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Mary McMahon
By Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a The Health Board researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Discussion Comments
By anon280811 — On Jul 20, 2012

To those who don't want to take vaccines: Don't take the vaccines. Don't vaccinate your children. It's fine. You are not allowed to cry and moan when your children or grandchildren die of something which is easily preventable. Don't do it. Let your kids get polio, smallpox, measles and chicken pox. As for herd immunity, who cares? Let an evolved smallpox for which a vaccine will not work, wipe us all out.

By anon252246 — On Mar 05, 2012

Public cleanliness programs are what brought about the disappearance of these diseases, not vaccines. The numbers show the already declining numbers, well before vaccines came onto the scene.

People lie, numbers don't.

I should also add, in many other countries where they don't vaccinate, these diseases don't exist.

By anon160504 — On Mar 16, 2011

Vaccination is proven, galen. In 1967 alone, 2 million people died from smallpox. now thanks to huge vaccination campaigns across the world smallpox has been eradicated. Immunisation works.

By anon145773 — On Jan 24, 2011

you vaccinate for tetanus because a tetanus vaccine protects you from tetanus for 10 years.

By anon140442 — On Jan 07, 2011

Galen, I think you might have something there. Otherwise, why to crop scientists worry so much about crop refuge areas?

By StreamFinder — On Oct 30, 2010

So what about the logic behind immunizations for tetanus and the like. There's not a herd immunization theory attached to that, since tetanus isn't contagious.

Could you give me some more vaccine logic information? I'm really interested about the whole herd immunity thing, and I can see how it would work for something like a hepatitis immunization, but what about other conditions?

By galen84basc — On Oct 30, 2010

I had heard that herd immunity was a myth. There's a book by Dr. Russel Blaylock that claims that the whole herd immunity theory is responsible for mass over-vaccinations that could actually be dangerous for society.

It's kind of like the logic behind the over-use of antibiotics. If you immunize everyone, then the disease can just grow stronger and stronger until it finds a way to overcome the vaccine.

And if that's not scary enough, then think of all the immunization side effects -- some people even die from getting immunizations!

Although I'm not totally against vaccinations and immunization programs, I do think that it merits some thought. We really don't want to be trading out a short term immunity for a long-term fight with super-diseases.

Just some food for thought.

By pharmchick78 — On Oct 30, 2010

You really can't stress enough the importance of herd immunity in enclosed areas like schools and very tightly packed urban cities.

Disease spreads quickly through human contact, and if immunity is not acquired, then much of the "herd" or group can fall ill.

This is why you so often hear of entire schools coming down with a cold at the same time, or epidemics starting in big cities. When everybody is just so closely packed together, it's difficult to avoid the spread of disease.

However, if you have taken the precautions of creating or encouraging a herd immunity, the disease suddenly stops. It may not have died out per se, but with the herd no longer vulnerable to it, there's no longer any risk of the disease becoming epidemic within the group.

And herd immunization is especially important for children, who tend to have less capable immune systems than adults. That's why one of the biggest proponents of herd immunity is the CDC. When you take the precautions to have hepatitis vaccines and the like -- in this case, an ounce of prevention is worth much more than a pound of cure.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a...

Learn more
The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.