Explained: What is herd immunity and how it will be achieved

NEW DELHI: Herd immunity against Covid-19 in India is likely to be achieved only in pockets given the many socio-economic groups in the country and maybe short-lived rather than long-lasting, say scientists as sero-surveillance data from New Delhi and Mumbai raise hopes of 'community protection' from the disease.
Much has been said about herd immunity with many experts touting it as one of the only two solutions for eradicating coronavirus. The other being vaccine.
What is herd immunity?
When most of a population is immune to an infectious disease, this provides indirect protection—or herd immunity (also called herd protection)—to those who are not immune to the disease.
For example —— There are 80 people infected with the virus in a community consisting of 100 people. Four out of five people who come in contact with a virus won't get sick because they already have the required antibodies. Hence, they would stop the virus from spreading further.
Usually, for highly infectious disease, such as coronavirus, around 70 to 90 per cent of the population needs to develop immunity to achieve herd immunity, according to John Hopkins University.
How will herd immunity be achieved in case of coronavirus?
There are two ways of developing immunity against novel coronavirus within a population — vaccine or herd immunity.
If there are no countermeasures — such as social distancing, masks, lockdowns — the virus would spread at a breakneck speed thus crippling the health infrastructure.
The idea is to slow the rate of growth of infection to a manageable level until a vaccine is available.
Even when the vaccine has been approved the infection can keep spreading. There would be newborns who may infect others before they are vaccinated, the immunity in adults may wane and it would take a considerable amount of time to vaccinate over 7 billion people on this planet.
However, the infection is unlikely to spread at such an explosive rate of growth because a majority of the population either has been exposed to the virus and hence develRead More – Source