COVID-19: What is Herd Immunity? Can it Work Against Coronavirus?


The British government’s chief scientific advisor has hinted at adopting the option of Herd Immunity to deal with the challenge of COVID-19 rapidly spreading in the world. WHO in their press conference also discussed the development of Herd Immunity amongst people. Indian people are considered to have developed a high level of Herd Immunity compared to other nations.  

What is Herd Immunity?

Herd Immunity means “To develop the immunity amongst the people in a society or group to prevent the spread of an infectious disease.”

The concept behind adopting this process is that if enough people are immunized, the chain of the spread of the disease in a society or group can be broken. Thus, the disease spread can be prevented amongst the people having weak Immunity.

Also Read: Essential Vitamins and Their Food Supplements

How does Herd Immunity work?

  • Epidemiologists use a standard known as ‘Basic Reproductive Number-R0’ to estimate the spread of infectious disease and the immune range required for it.
  • It tells how many other people can get infected with that disease when they come in contact with a single case or patient.
  • Having more than one R0 means that one person can infect many other individuals.
  • According to scientific evidence, a person suffering from Measles can infect 12-18 other people while a person suffering from Influenza can infect about 1-4 persons.
  • Based on the evidence currently available from China, experts believe that R0 of COVID-19 can be between 2 and 3.

Any infection can spread in a society/group in three ways:

  1. In the first case, where no person in the group has been vaccinated, if there are two cases of R0 with 1 coefficient, then the whole community can be infected.
  2. In the second case, if only a few people of a group have been vaccinated, then other people of that group may be infected, except those.
  3. But if enough people in a group are immunized, then only those people of the group who are very weak or who do not have strong Immunity will be infected.

How to achieve Herd Immunity?

According to experts, the success of Herd Immunity depends on many factors such as:

  • The effect of the vaccine to prevent infection
  • The duration of infection and the effect of the vaccine
  • The part of the group that is responsible for the spread of the infection.

Mathematically it is determined by a fixed number, which is called the Herd Immunity Threshold. It refers to the number of people on whom the infection cannot affect and communicate. The range is 80–85% for polio while 95% for measles. Based on the data, this limit for COVID-19 is around 60%. That means 60% of the people in a group need to be immunized to get Herd Immunity against COVID-19.

Also Read: After Corona, America will Bear the Brunt of Nature: Expert Warns

Herd Immunity challenges in dealing with COVID-19

According to experts, it will be risky to allow more people from society to get infected with COVID-19.

The development of COVID-19 Immunity in such large amounts can take a long time. This can lead to many risks. The people with co-morbidities like heart disease and high blood pressure are most vulnerable to this infection.

In this process, Immunity can develop in those people who once become infected can get rid of the infection. But in the context of COVID-19, there is no evidence of the success of this process. Even, it cannot be ensured that once cured, no person will be infected with the disease again.

In this process, the burden on health centers who are already working under pressure will be increased. This may turn into the wrong decision at the time of this disaster.


Please follow and like us:

Leave a Reply

Your email address will not be published. Required fields are marked *