Prevention of Covid-19 vs Herd Immunity?

what is herd immunity?
Herd immunity is also called community immunity. Herd immunity happens when many people in a community become immune to an infectious disease that it stops the disease from spreading.

How can we achieve Herd immunity?
Herd immunity can be achieved in 2 ways.

1. Critical percentage of population contract the disease and in time build up an immune response (Natural Immunity)
2. Critical percentage of population are vaccinated against the disease to achieve immunity.

So, what is this critical percentage of population? For some diseases, herd immunity can go into effect when 40 percent of the people in a population become immune to the disease. But in most cases, 80 to 95 percent of the population must be immune to the disease to stop its spread. According to WHO's Chief Scientist, Dr Soumya Swaminathan at least 60 to 70% of the population must become immune to break the chain of transmission of covid-19.

How does it work?
When you contract an infection, the immune system gets triggered to produce antibodies against the microbe causing infection which leads to natural immunity. If you contract the same infection again, the antibodies that dealt with the microbe earlier can attack it before it spreads and makes you ill. For example, if you had chickenpox as a child, you most likely won’t get it again, even if you’re around someone with it.

If a certain percentage of population gets infected and has developed antibodies, these people act as a barrier to break the chain of transmission. So, the population not infected and who are at risk can be protected.

It’s the same herd immunity principle can be achieved using vaccinations. When 95% of population get vaccinated the remaining 5% population who could not be vaccinated for any reason can be protected from getting infected. So, vaccination can lead to individual immunity and when major percentage of population get vaccinated it leads to herd immunity.

Will it work for Covid-19?
With people naturally getting infected developing herd immunity will take long time and it will be at the cost of several human lives. Even if 1% of people who get infected are ultimately going to die, then this can be a huge number of people if we look at the global population. So,according to experts it will not be right to try to achieve herd immunity by allowing many people get infected. Also, since few cases of reinfection is reported world over it again suggests we should not try for a naturally acquired herd immunity.

With vaccination yes, it is definitely possible as per various scientists. Scientists believe that we should aim for acquiring herd immunity with vaccine as it is reliable and also can be achieved without any collateral damage.

So what next till vaccine?
Just continue what we were doing last few months more rigorously as we are moving towards new normal. Practice social distancing, use alcohol-based sanitisers, wear reusable face covers or masks at all times in public places, wash your hands frequently and thoroughly with soap and water, avoid touching eyes, nose and mouth and cover them with tissue/handkerchief while sneezing or coughing. This is the only way, we can prevent the spread of the infection and safeguard ourselves from its contraction till the arrival of vaccine so that hospitalisations and loss of human lives can be prevented.