According to the World Health Organisation, herd immunity occurs when a large portion of a community becomes immune to a disease, making the spread of that disease from person to person unlikely. In case of COVID-19, at least 60 to 70 per cent of the population need to have immunity to break the chain of transmission. Currently, the scientists worldwide are working at breakneck speed to develop an effective vaccine for the coronavirus. Their ultimate goal is to immunize enough of the world's population to reach herd immunity.