We must have heard of ‘herd immunity’ by now. After so many dialogue around the topic everyone is fascinated to know what is herd immunity and why is it important.

Is herd immunity a fact ? Let me ascertain you, it is not a recent concept. We have implemented it in past too, to control various diseases. Below it is explained in detail.

1. What is herd immunity and why is it important ?


When a significant proportion of population has immunity power against a particular microbe then rest of the vulnerable population is not infected by that germ. 

But how? The answer is clear and simple. When a large segment of people are immune against a disease causing agent, then it can not spread from one person to another. As the transmission chain breaks, the microbe can no longer reach less immune persons. So the susceptible group of people with frail immune system get an indirect advantage. This is how herd immunity works.

2. What is “Herd immunity threshold” or herd immunity percentage ?

After having a clear knowledge of what is herd immunity, let us understand what is herd immunity threshold. It is the proportion of population that must have immunity power to a disease in order to prevent it from spreading person to person (CDC)

Usually ‘herd immunity threshold’ is 70-90 percentage, as per John Hopkins data. This is also called herd immunity percentage in layman’s term.

As per some experts ‘herd immunity threshold’ is 60 percentage for coronavirus. That means at least 60 percentage population should be immune to stop spread of covid-19. But as statistics and nature of this pathogen is yet not clear we are still not sure about this data.

3. Heating debate around herd immunity and corona virus.


Very recently when corona virus cases started growing no one was aware of the nature of this virus. Some leaders and experts had retained their confidence in concept of naturally attained herd immunity.

Heating debate around it started when UK’s Government Chief Scientific Adviser Sir Patrick Vallance explained a strategy to control corona virus UK. He advised to let people get infected spontaneously, without imposing any restrictions to attain 60% immunity in UK population.

This step received world wide criticism. ‘Imperialism College of London’ also warned against It’s tragic consequences.

Later UK pulled back it’s own statement when corona virus UK progressed uncontrollably. Now UK is following social distancing and isolation system. “Stay home stay safe” is the new norm.

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4. Loop holes of natural ‘herd immunity’ theory in case of Covid-19.


The idea of natural ‘herd immunity’ sounds simple, swift and cheap. Many countries relied on it in preliminary days of virus outbreak. But they had to ultimately pay a massive price. It is because SARS CoV-2 is distinct from rest viruses in nature.

  • It is an absolutely new virus. No one has immunity so far as none is exposed to it before
  • It has high infectivity. This virus is capable of infecting a huge population of people in very short period of time.
  • Corona virus has high mortality rate too in relation to other diseases. When seasonal flu has mortality rate of just 0.1 %, corona virus has 3.4% mortality rate world wide.

3.4% may appear as a meager number. But if within a brief span of time a large population gets affected then 3.4% of these people will be a substantial figure. Further a considerable fraction of people ( apart from those who are dying ) will suffer morbidity. They will require oxygen support and ICU facilities. It will compromise and overwhelm medical system. 

This situation arose in many countries with best health care system. There doctors had to triage and decide which patients to treat and which patients to leave and let die.

So social distancing and other precautions should be maintained. Otherwise within a matter of few months whole world will get infected. Then whole mankind will confront the same problem what many developed countries are facing. For developing countries it can be even worse. 

5. Alternative solutions:


To attain natural herd immunity a lot of lives has to be risked. Hence we need a more acceptable alternative to it. Below are 2 such solutions discussed by experts. 

1st proposed solution:

Some professional had stated a solution to this issue. They proposed to isolate young and healthy people from old people and people with weakened immune system. Then infect the young population deliberately with corona virus so as to develop immunity power for least 60% of masses i.e. herd immunity.

This solution sounds so impractical to even think of. So we definitely need a better and a more rational solution.

2nd proposed solution :


In case of ailments like measles, chicken pox, polio etc we are able to control the spread by the concept of herd immunity. Here we have produced vaccines which provide immunity power against a particular germ by artificial means.

But developing a vaccine is going to take another 1 year or so. It will be validated only after going through several trials. 

Till we create a coronavirus vaccine, we have to follow social distancing and other precautions, to curtail the virus spread. By following proper cautions we will buy some time to expand health care infrastructure, and procure medications, medical equipments etc. 

This solution is realistic enough to implement. There are rays of hope in vaccine development. We are hopeful to get an effective coronavirus vaccine soon. Till then we have to acquire a new style of living with maintaining social distancing, hand hygiene and using face mask. 

ALSO READ : How does hand sanitizer kill viruses? 15 interesting facts about hand sanitizer people will never tell you.

Concluding words:

Now we are clear, what is herd immunity and why is it important. We also got to know how herd immunity works.

Everything explained here is my personal point of view. I have taken reference from some reliable sources that I have mentioned below. 

If you have anything to further add on, then feel free to mention in the comment section below. If this post is likeable enough then share with your family and friends and take a step further to spread awareness.