Achieving Herd Immunity Through Vaccinations

What is Herd Immunity?

Herd immunity, also referred as population immunity, is a concept used for vaccination, in which a population can be protected from a certain virus if a threshold of vaccination is reached. Herd immunity is achieved by protecting people from a virus, not exposing them to it.

With herd immunity, the vast majority of a population are vaccinated, lowering the overall amount of virus able to spread in the whole population, breaking any chains of transmission. As a result, not every single person needs to be vaccinated to be protected, which helps ensure vulnerable groups who cannot get vaccinated are kept safe.

Why is Herd Immunity Important?

When enough community members are immune to a virus so that it inhibits spread, even those who are not vaccinated will be protected. The “herd” collectively provides insulated safety to all members, which is important for those who are too high-risk for certain vaccinations.

Some reasons why people cannot get certain vaccinations include:

  • Age
  • Allergies
  • Pregnancy
  • Recent blood transfusions
  • Underlying medical conditions
  • Weakened immune system

Experts estimate that herd immunity would require at least 60-70% of the U.S. population to have COVID-19 immunity, that translates to roughly 200 million people. The U.S. population is around 328 millionThe Science Behind How Herd Immunity Works


In a community where very few are immune to a virus, a disease can spread rapidly and lead to an outbreak. As individuals acquire immunity, wither through infection or a vaccine, the disease spreads more slowly because fewer people can pass it on.







In a community where enough members are vaccinated, the disease will stop spreading because the virus will not be able to find susceptible hosts.





 Is it possible to achieve herd immunity without a vaccine?Because the herd immunity threshold is so high, achieving herd immunity without a vaccine is unlikely. Attempts to reach herd immunity through exposing people to a virus are scientifically problematic and unethical. Letting COVID-19 spread through populations through natural infection, of any age or health status will lead to unnecessary infections, suffering, and death.

There is still much to learn without immunity to COVID-19. Most people who are infected with COVID-19 develop an immune response within the first few weeks, but we don’t know how strong or lasting that immune response is, or how it differs for different people. There have also been reports of people infected with COVID-19 for a second time.

Until we better understand COVID-19 immunity, it will not be possible to know how much of a population is immune and how long that immunity will last for, let alone make future predictions. These challenges should prevent any plans that try to increase immunity within a population by allowing people to get infected.

With a vaccine you can achieve immunity and herd immunity safely.


World Health Organization (WHO):'Herd%20immunity'%2C,exposing%20them%20to%20it

American Lung Association:,assuming%20lasting%20immunity%20is%20possible

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